diff --git a/.rubocop/default.yml b/.rubocop/default.yml
index ac9e8e0c4..a6252d172 100644
--- a/.rubocop/default.yml
+++ b/.rubocop/default.yml
@@ -273,6 +273,9 @@ Style/StringConcatenation:
   Exclude:
     - "config/routes/**/*"
 
+Style/RegexpLiteral:
+  EnforcedStyle: percent_r
+
 # RSpec tests
 Style/NumericPredicate:
   Description: >-
diff --git a/app/controllers/application_controller/handles_errors.rb b/app/controllers/application_controller/handles_errors.rb
index 651fe996a..20610f2db 100644
--- a/app/controllers/application_controller/handles_errors.rb
+++ b/app/controllers/application_controller/handles_errors.rb
@@ -82,11 +82,11 @@ module ApplicationController::HandlesErrors
       error: e.message
     }
 
-    if e.message =~ /Validation failed: (.+?)(,|$)/i
+    if e.message =~ %r{Validation failed: (.+?)(,|$)}i
       data[:error_human] = $1
-    elsif e.message.match?(/(already exists|duplicate key|duplicate entry)/i)
+    elsif e.message.match?(%r{(already exists|duplicate key|duplicate entry)}i)
       data[:error_human] = 'Object already exists!'
-    elsif e.message =~ /null value in column "(.+?)" violates not-null constraint/i || e.message =~ /Field '(.+?)' doesn't have a default value/i
+    elsif e.message =~ %r{null value in column "(.+?)" violates not-null constraint}i || e.message =~ %r{Field '(.+?)' doesn't have a default value}i
       data[:error_human] = "Attribute '#{$1}' required!"
     elsif e.message == 'Exceptions::Forbidden'
       data[:error]       = 'Not authorized'
diff --git a/app/controllers/channels_email_controller.rb b/app/controllers/channels_email_controller.rb
index eff163f8d..ed4237c14 100644
--- a/app/controllers/channels_email_controller.rb
+++ b/app/controllers/channels_email_controller.rb
@@ -224,7 +224,7 @@ class ChannelsEmailController < ApplicationController
 
       Channel.where(area: 'Email::Notification').each do |channel|
         active = false
-        if adapter.match?(/^#{channel.options[:outbound][:adapter]}$/i)
+        if adapter.match?(%r{^#{channel.options[:outbound][:adapter]}$}i)
           active = true
           channel.options = {
             outbound: {
diff --git a/app/controllers/concerns/creates_ticket_articles.rb b/app/controllers/concerns/creates_ticket_articles.rb
index 65570ea5d..0d59f20d1 100644
--- a/app/controllers/concerns/creates_ticket_articles.rb
+++ b/app/controllers/concerns/creates_ticket_articles.rb
@@ -37,7 +37,7 @@ module CreatesTicketArticles
       clean_params.delete(:sender)
       clean_params.delete(:origin_by_id)
       type = Ticket::Article::Type.lookup(id: clean_params[:type_id])
-      if !type.name.match?(/^(note|web)$/)
+      if !type.name.match?(%r{^(note|web)$})
         clean_params[:type_id] = Ticket::Article::Type.lookup(name: 'note').id
       end
       clean_params.delete(:type)
@@ -91,12 +91,12 @@ module CreatesTicketArticles
         preferences_keys.each do |key|
           next if !attachment[key]
 
-          store_key = key.tr('-', '_').camelize.gsub(/(.+)([A-Z])/, '\1_\2').tr('_', '-')
+          store_key = key.tr('-', '_').camelize.gsub(%r{(.+)([A-Z])}, '\1_\2').tr('_', '-')
           preferences[store_key] = attachment[key]
         end
 
         begin
-          base64_data = attachment[:data].gsub(/[\r\n]/, '')
+          base64_data = attachment[:data].gsub(%r{[\r\n]}, '')
           attachment_data = Base64.strict_decode64(base64_data)
         rescue ArgumentError
           raise Exceptions::UnprocessableEntity, "Invalid base64 for attachment with index '#{index}'"
diff --git a/app/controllers/getting_started_controller.rb b/app/controllers/getting_started_controller.rb
index 4671203a6..89a793288 100644
--- a/app/controllers/getting_started_controller.rb
+++ b/app/controllers/getting_started_controller.rb
@@ -124,7 +124,7 @@ curl http://localhost/api/v1/getting_started -v -u #{login}:#{password}
     end
 
     # validate image
-    if params[:logo] && params[:logo] =~ /^data:image/i
+    if params[:logo] && params[:logo] =~ %r{^data:image}i
       file = StaticAssets.data_url_attributes(params[:logo])
       if !file[:content] || !file[:mime_type]
         messages[:logo] = 'Unable to process image upload.'
@@ -150,7 +150,7 @@ curl http://localhost/api/v1/getting_started -v -u #{login}:#{password}
     end
 
     # save image
-    if params[:logo] && params[:logo] =~ /^data:image/i
+    if params[:logo] && params[:logo] =~ %r{^data:image}i
 
       # data:image/png;base64
       file = StaticAssets.data_url_attributes(params[:logo])
@@ -159,7 +159,7 @@ curl http://localhost/api/v1/getting_started -v -u #{login}:#{password}
       StaticAssets.store_raw(file[:content], file[:mime_type])
     end
 
-    if params[:logo_resize] && params[:logo_resize] =~ /^data:image/i
+    if params[:logo_resize] && params[:logo_resize] =~ %r{^data:image}i
 
       # data:image/png;base64
       file = StaticAssets.data_url_attributes(params[:logo_resize])
diff --git a/app/controllers/import_otrs_controller.rb b/app/controllers/import_otrs_controller.rb
index b9e109ae5..83de2906c 100644
--- a/app/controllers/import_otrs_controller.rb
+++ b/app/controllers/import_otrs_controller.rb
@@ -23,10 +23,10 @@ class ImportOtrsController < ApplicationController
     }
 
     response = UserAgent.request(params[:url])
-    if !response.success? && response.code.to_s !~ /^40.$/
+    if !response.success? && response.code.to_s !~ %r{^40.$}
       message_human = ''
       translation_map.each do |key, message|
-        if response.error.to_s.match?(/#{Regexp.escape(key)}/i)
+        if response.error.to_s.match?(%r{#{Regexp.escape(key)}}i)
           message_human = message
         end
       end
@@ -86,7 +86,7 @@ class ImportOtrsController < ApplicationController
           message_human: migrator_response['Error']
         }
       end
-    elsif response.body.match?(/(otrs\sag|otrs\.com|otrs\.org)/i)
+    elsif response.body.match?(%r{(otrs\sag|otrs\.com|otrs\.org)}i)
       result = {
         result:        'invalid',
         message_human: 'Host found, but no OTRS migrator is installed!'
diff --git a/app/controllers/import_zendesk_controller.rb b/app/controllers/import_zendesk_controller.rb
index a68a3dbe1..ad4d6c9f1 100644
--- a/app/controllers/import_zendesk_controller.rb
+++ b/app/controllers/import_zendesk_controller.rb
@@ -27,7 +27,7 @@ class ImportZendeskController < ApplicationController
     if !response.success?
       message_human = ''
       translation_map.each do |key, message|
-        if response.error.to_s.match?(/#{Regexp.escape(key)}/i)
+        if response.error.to_s.match?(%r{#{Regexp.escape(key)}}i)
           message_human = message
         end
       end
@@ -40,7 +40,7 @@ class ImportZendeskController < ApplicationController
     end
 
     # since 2016-10-15 a redirect to a marketing page has been implemented
-    if !response.body.match?(/#{params[:url]}/)
+    if !response.body.match?(%r{#{params[:url]}})
       render json: {
         result:        'invalid',
         message_human: 'Hostname not found!',
diff --git a/app/controllers/integration/check_mk_controller.rb b/app/controllers/integration/check_mk_controller.rb
index 260d232d2..879a11f1a 100644
--- a/app/controllers/integration/check_mk_controller.rb
+++ b/app/controllers/integration/check_mk_controller.rb
@@ -61,7 +61,7 @@ UserAgent: #{request.env['HTTP_USER_AGENT'] || '-'}
           internal:  false,
         )
       end
-      if (!auto_close && params[:state].match(/#{state_recovery_match}/i)) || !params[:state].match(/#{state_recovery_match}/i)
+      if (!auto_close && params[:state].match(%r{#{state_recovery_match}}i)) || !params[:state].match(%r{#{state_recovery_match}}i)
         render json: {
           result:     'ticket already open, added note',
           ticket_ids: ticket_ids_found,
@@ -71,7 +71,7 @@ UserAgent: #{request.env['HTTP_USER_AGENT'] || '-'}
     end
 
     # check if service is recovered
-    if auto_close && params[:state].present? && params[:state].match(/#{state_recovery_match}/i)
+    if auto_close && params[:state].present? && params[:state].match(%r{#{state_recovery_match}}i)
       if ticket_ids_found.blank?
         render json: {
           result: 'no open tickets found, ignore action',
diff --git a/app/controllers/integration/smime_controller.rb b/app/controllers/integration/smime_controller.rb
index 4751557dc..e1771e14f 100644
--- a/app/controllers/integration/smime_controller.rb
+++ b/app/controllers/integration/smime_controller.rb
@@ -42,7 +42,7 @@ class Integration::SMIMEController < ApplicationController
       string = params[:file].read.force_encoding('utf-8')
     end
 
-    items = string.scan(/.+?-+END(?: TRUSTED)? CERTIFICATE-+/mi).each_with_object([]) do |cert, result|
+    items = string.scan(%r{.+?-+END(?: TRUSTED)? CERTIFICATE-+}mi).each_with_object([]) do |cert, result|
       result << SMIMECertificate.create!(public_key: cert)
     end
 
diff --git a/app/controllers/monitoring_controller.rb b/app/controllers/monitoring_controller.rb
index 00795fbdd..5a7101791 100644
--- a/app/controllers/monitoring_controller.rb
+++ b/app/controllers/monitoring_controller.rb
@@ -308,7 +308,7 @@ curl http://localhost/api/v1/monitoring/amount_check?token=XXX&periode=1h
     raise Exceptions::UnprocessableEntity, 'periode is missing!' if params[:periode].blank?
 
     scale = params[:periode][-1, 1]
-    raise Exceptions::UnprocessableEntity, 'periode need to have s, m, h or d as last!' if !scale.match?(/^(s|m|h|d)$/)
+    raise Exceptions::UnprocessableEntity, 'periode need to have s, m, h or d as last!' if !scale.match?(%r{^(s|m|h|d)$})
 
     periode = params[:periode][0, params[:periode].length - 1]
     raise Exceptions::UnprocessableEntity, 'periode need to be an integer!' if periode.to_i.zero?
diff --git a/app/controllers/object_manager_attributes_controller.rb b/app/controllers/object_manager_attributes_controller.rb
index 6f0c999e0..85899f71f 100644
--- a/app/controllers/object_manager_attributes_controller.rb
+++ b/app/controllers/object_manager_attributes_controller.rb
@@ -76,7 +76,7 @@ class ObjectManagerAttributesController < ApplicationController
     @permitted_params ||= begin
       permitted = params.permit!.to_h
 
-      if permitted[:data_type].match?(/^(boolean)$/) && permitted[:data_option][:options]
+      if permitted[:data_type].match?(%r{^(boolean)$}) && permitted[:data_option][:options]
         # rubocop:disable Lint/BooleanSymbol
         if permitted[:data_option][:options][:false]
           permitted[:data_option][:options][false] = permitted[:data_option][:options].delete(:false)
@@ -98,7 +98,7 @@ class ObjectManagerAttributesController < ApplicationController
       if permitted[:data_option]
 
         if !permitted[:data_option].key?(:default)
-          permitted[:data_option][:default] = if permitted[:data_type].match?(/^(input|select|tree_select)$/)
+          permitted[:data_option][:default] = if permitted[:data_type].match?(%r{^(input|select|tree_select)$})
                                                 ''
                                               end
         end
diff --git a/app/controllers/settings_controller.rb b/app/controllers/settings_controller.rb
index 5368bb221..6207f632d 100644
--- a/app/controllers/settings_controller.rb
+++ b/app/controllers/settings_controller.rb
@@ -43,7 +43,7 @@ class SettingsController < ApplicationController
     end
 
     # validate image
-    if !clean_params[:logo].match?(/^data:image/i)
+    if !clean_params[:logo].match?(%r{^data:image}i)
       render json: {
         result:  'invalid',
         message: 'Invalid payload, need data:image in logo param',
@@ -66,7 +66,7 @@ class SettingsController < ApplicationController
 
     # store resized image 1:1
     setting = Setting.lookup(name: 'product_logo')
-    if params[:logo_resize] && params[:logo_resize] =~ /^data:image/i
+    if params[:logo_resize] && params[:logo_resize] =~ %r{^data:image}i
 
       # data:image/png;base64
       file = StaticAssets.data_url_attributes(params[:logo_resize])
diff --git a/app/controllers/tickets_controller.rb b/app/controllers/tickets_controller.rb
index 5c6d2378a..094a00e5b 100644
--- a/app/controllers/tickets_controller.rb
+++ b/app/controllers/tickets_controller.rb
@@ -96,7 +96,7 @@ class TicketsController < ApplicationController
     end
 
     # try to create customer if needed
-    if clean_params[:customer_id].present? && clean_params[:customer_id] =~ /^guess:(.+?)$/
+    if clean_params[:customer_id].present? && clean_params[:customer_id] =~ %r{^guess:(.+?)$}
       email_address = $1
       email_address_validation = EmailAddressValidation.new(email_address)
       if !email_address_validation.valid_format?
diff --git a/app/helpers/knowledge_base_rich_text_helper.rb b/app/helpers/knowledge_base_rich_text_helper.rb
index b9a00dd2b..1409f998d 100644
--- a/app/helpers/knowledge_base_rich_text_helper.rb
+++ b/app/helpers/knowledge_base_rich_text_helper.rb
@@ -27,7 +27,7 @@ module KnowledgeBaseRichTextHelper
   end
 
   def prepare_rich_text_videos(input)
-    input.gsub(/\((\s*)widget:(\s*)video\W([\s\S])+?\)/) do |match|
+    input.gsub(%r{\((\s*)widget:(\s*)video\W([\s\S])+?\)}) do |match|
       settings = match
         .slice(1...-1)
         .split(',')
diff --git a/app/jobs/communicate_facebook_job.rb b/app/jobs/communicate_facebook_job.rb
index a3acaad4e..5d451eff4 100644
--- a/app/jobs/communicate_facebook_job.rb
+++ b/app/jobs/communicate_facebook_job.rb
@@ -15,7 +15,7 @@ class CommunicateFacebookJob < ApplicationJob
     log_error(article, "Can't find ticket.preferences for Ticket.find(#{article.ticket_id})") if !ticket.preferences
     log_error(article, "Can't find ticket.preferences['channel_id'] for Ticket.find(#{article.ticket_id})") if !ticket.preferences['channel_id']
     channel = Channel.lookup(id: ticket.preferences['channel_id'])
-    log_error(article, "Channel.find(#{channel.id}) isn't a twitter channel!") if !channel.options[:adapter].match?(/\Afacebook/i)
+    log_error(article, "Channel.find(#{channel.id}) isn't a twitter channel!") if !channel.options[:adapter].match?(%r{\Afacebook}i)
 
     # check source object id
     if !ticket.preferences['channel_fb_object_id']
diff --git a/app/jobs/communicate_telegram_job.rb b/app/jobs/communicate_telegram_job.rb
index e808199b2..88fdd41a9 100644
--- a/app/jobs/communicate_telegram_job.rb
+++ b/app/jobs/communicate_telegram_job.rb
@@ -31,7 +31,7 @@ class CommunicateTelegramJob < ApplicationJob
       result = api.sendMessage(chat_id, article.body)
       me = api.getMe()
       article.attachments.each do |file|
-        parts = file.filename.split(/^(.*)(\..+?)$/)
+        parts = file.filename.split(%r{^(.*)(\..+?)$})
         t = Tempfile.new([parts[1], parts[2]])
         t.binmode
         t.write(file.content)
diff --git a/app/jobs/communicate_twitter_job.rb b/app/jobs/communicate_twitter_job.rb
index c4ecd152d..edb5ab634 100644
--- a/app/jobs/communicate_twitter_job.rb
+++ b/app/jobs/communicate_twitter_job.rb
@@ -30,7 +30,7 @@ class CommunicateTwitterJob < ApplicationJob
     end
 
     log_error(article, "No such channel id #{ticket.preferences['channel_id']}") if !channel
-    log_error(article, "Channel.find(#{channel.id}) isn't a twitter channel!") if !channel.options[:adapter].try(:match?, /\Atwitter/i)
+    log_error(article, "Channel.find(#{channel.id}) isn't a twitter channel!") if !channel.options[:adapter].try(:match?, %r{\Atwitter}i)
 
     begin
       tweet = channel.deliver(
diff --git a/app/models/application_model/can_assets.rb b/app/models/application_model/can_assets.rb
index 035e5f37b..6697d7e51 100644
--- a/app/models/application_model/can_assets.rb
+++ b/app/models/application_model/can_assets.rb
@@ -81,12 +81,12 @@ get assets and record_ids of selector
         attribute_ref_class = ::User
         item_ids            = []
         Array(content['recipient']).each do |identifier|
-          next if identifier !~ /\Auserid_(\d+)\z/
+          next if identifier !~ %r{\Auserid_(\d+)\z}
 
           item_ids.push($1)
         end
       else
-        reflection = attribute[1].sub(/_id$/, '')
+        reflection = attribute[1].sub(%r{_id$}, '')
         next if !models[attribute_class]
         next if !models[attribute_class][:reflections]
         next if !models[attribute_class][:reflections][reflection]
diff --git a/app/models/avatar.rb b/app/models/avatar.rb
index 562e0d4eb..0a31cea99 100644
--- a/app/models/avatar.rb
+++ b/app/models/avatar.rb
@@ -110,10 +110,10 @@ add avatar by url
         content = data[:url].read
         filename = data[:url].path
         mime_type = 'image'
-        if filename.match?(/\.png/i)
+        if filename.match?(%r{\.png}i)
           mime_type = 'image/png'
         end
-        if filename.match?(/\.(jpg|jpeg)/i)
+        if filename.match?(%r{\.(jpg|jpeg)}i)
           mime_type = 'image/jpeg'
         end
         data[:resize] ||= {}
@@ -132,7 +132,7 @@ add avatar by url
         # twitter workaround to get bigger avatar images
         # see also https://dev.twitter.com/overview/general/user-profile-images-and-banners
         if url.match?(%r{//pbs.twimg.com/}i)
-          url.sub!(/normal\.(png|jpg|gif)$/, 'bigger.\1')
+          url.sub!(%r{normal\.(png|jpg|gif)$}, 'bigger.\1')
         end
 
         # fetch image
@@ -151,10 +151,10 @@ add avatar by url
         end
         logger.info "Fetchd image '#{url}', http code: #{response.code}"
         mime_type = 'image'
-        if url.match?(/\.png/i)
+        if url.match?(%r{\.png}i)
           mime_type = 'image/png'
         end
-        if url.match?(/\.(jpg|jpeg)/i)
+        if url.match?(%r{\.(jpg|jpeg)}i)
           mime_type = 'image/jpeg'
         end
 
diff --git a/app/models/calendar.rb b/app/models/calendar.rb
index 5ce689e7c..7b822d8a8 100644
--- a/app/models/calendar.rb
+++ b/app/models/calendar.rb
@@ -27,7 +27,7 @@ returns calendar object
   def self.init_setup(ip = nil)
 
     # ignore client ip if not public ip
-    if ip && ip =~ /^(::1|127\.|10\.|172\.1[6-9]\.|172\.2[0-9]\.|172\.3[0-1]\.|192\.168\.)/
+    if ip && ip =~ %r{^(::1|127\.|10\.|172\.1[6-9]\.|172\.2[0-9]\.|172\.3[0-1]\.|192\.168\.)}
       ip = nil
     end
 
@@ -214,7 +214,7 @@ returns
   end
 
   def self.fetch_parse(location)
-    if location.match?(/^http/i)
+    if location.match?(%r{^http}i)
       result = UserAgent.get(location)
       if !result.success?
         raise result.error
@@ -262,7 +262,7 @@ returns
     comment = comment.to_utf8(fallback: :read_as_sanitized_binary)
 
     # ignore daylight saving time entries
-    return if comment.match?(/(daylight saving|sommerzeit|summertime)/i)
+    return if comment.match?(%r{(daylight saving|sommerzeit|summertime)}i)
 
     [day, comment]
   end
diff --git a/app/models/channel/driver/imap.rb b/app/models/channel/driver/imap.rb
index 90b95b4ff..e460feed5 100644
--- a/app/models/channel/driver/imap.rb
+++ b/app/models/channel/driver/imap.rb
@@ -226,7 +226,7 @@ example
         headers = self.class.extract_rfc822_headers(message_meta)
         subject = headers['Subject']
         next if !subject
-        next if !subject.match?(/#{verify_string}/)
+        next if !subject.match?(%r{#{verify_string}})
 
         Rails.logger.info " - verify email #{verify_string} found"
         timeout(600) do
@@ -406,7 +406,7 @@ returns
     array = string
               .gsub("\r\n\t", ' ') # Some servers (e.g. microsoft365) may put attribute value on a separate line and tab it
               .lines(chomp: true)
-              .map { |line| line.split(/:\s*/, 2).map(&:strip) }
+              .map { |line| line.split(%r{:\s*}, 2).map(&:strip) }
 
     array.each { |elem| elem.append(nil) if elem.one? }
 
diff --git a/app/models/channel/driver/pop3.rb b/app/models/channel/driver/pop3.rb
index c73231585..5c34afd85 100644
--- a/app/models/channel/driver/pop3.rb
+++ b/app/models/channel/driver/pop3.rb
@@ -91,7 +91,7 @@ returns
         next if !mail
 
         # check how many content messages we have, for notice used
-        if !mail.match?(/(X-Zammad-Ignore: true|X-Zammad-Verify: true)/)
+        if !mail.match?(%r{(X-Zammad-Ignore: true|X-Zammad-Verify: true)})
           content_messages += 1
           break if content_max_check < content_messages
         end
@@ -117,7 +117,7 @@ returns
         next if !mail
 
         # check if verify message exists
-        next if !mail.match?(/#{verify_string}/)
+        next if !mail.match?(%r{#{verify_string}})
 
         Rails.logger.info " - verify email #{verify_string} found"
         m.delete
@@ -149,7 +149,7 @@ returns
       next if !mail
 
       # ignore verify messages
-      if mail.match?(/(X-Zammad-Ignore: true|X-Zammad-Verify: true)/) && mail =~ /X-Zammad-Verify-Time:\s(.+?)\s/
+      if mail.match?(%r{(X-Zammad-Ignore: true|X-Zammad-Verify: true)}) && mail =~ %r{X-Zammad-Verify-Time:\s(.+?)\s}
         begin
           verify_time = Time.zone.parse($1)
           if verify_time > Time.zone.now - 30.minutes
diff --git a/app/models/channel/driver/smtp.rb b/app/models/channel/driver/smtp.rb
index a1f32fe39..4bba2f6c7 100644
--- a/app/models/channel/driver/smtp.rb
+++ b/app/models/channel/driver/smtp.rb
@@ -36,7 +36,7 @@ class Channel::Driver::Smtp
     if !options.key?(:domain)
       # set fqdn, if local fqdn - use domain of sender
       fqdn = Setting.get('fqdn')
-      if fqdn =~ /(localhost|\.local^|\.loc^)/i && (attr['from'] || attr[:from])
+      if fqdn =~ %r{(localhost|\.local^|\.loc^)}i && (attr['from'] || attr[:from])
         domain = Mail::Address.new(attr['from'] || attr[:from]).domain
         if domain
           fqdn = domain
diff --git a/app/models/channel/email_build.rb b/app/models/channel/email_build.rb
index 6f78de39e..4deb0b58a 100644
--- a/app/models/channel/email_build.rb
+++ b/app/models/channel/email_build.rb
@@ -157,7 +157,7 @@ returns
 =end
 
   def self.recipient_line(realname, email)
-    return "#{realname} <#{email}>" if realname.match?(/^[A-z]+$/i)
+    return "#{realname} <#{email}>" if realname.match?(%r{^[A-z]+$}i)
 
     "\"#{realname.gsub('"', '\"')}\" <#{email}>"
   end
@@ -175,7 +175,7 @@ Check if string is a complete html document. If not, add head and css styles.
     # apply mail client fixes
     html = Channel::EmailBuild.html_mail_client_fixes(html)
 
-    return html if html.match?(/<html>/i)
+    return html if html.match?(%r{<html>}i)
 
     html_email_body = File.read(Rails.root.join('app/views/mailer/application_wrapper.html.erb').to_s)
 
@@ -198,7 +198,7 @@ Add/change markup to display html in any mail client nice.
 
     # https://github.com/martini/zammad/issues/165
     new_html = html.gsub('<blockquote type="cite">', '<blockquote type="cite" style="border-left: 2px solid blue; margin: 0 0 16px; padding: 8px 12px 8px 12px;">')
-    new_html.gsub!(/<p>/mxi, '<p style="margin: 0;">')
+    new_html.gsub!(%r{<p>}mxi, '<p style="margin: 0;">')
     new_html.gsub!(%r{</?hr>}mxi, '<hr style="margin-top: 6px; margin-bottom: 6px; border: 0; border-top: 1px solid #dfdfdf;">')
     new_html
   end
diff --git a/app/models/channel/email_parser.rb b/app/models/channel/email_parser.rb
index e6646f025..e46085ca5 100644
--- a/app/models/channel/email_parser.rb
+++ b/app/models/channel/email_parser.rb
@@ -4,7 +4,7 @@
 
 class Channel::EmailParser
   PROZESS_TIME_MAX = 180
-  EMAIL_REGEX = /.+@.+/.freeze
+  EMAIL_REGEX = %r{.+@.+}.freeze
   RECIPIENT_FIELDS = %w[to cc delivered-to x-original-to envelope-to].freeze
   SENDER_FIELDS = %w[from reply-to return-path sender].freeze
   EXCESSIVE_LINKS_MSG = 'This message cannot be displayed because it contains over 5,000 links. Download the raw message below and open it via an Email client if you still wish to view it.'.freeze
@@ -351,7 +351,7 @@ returns
     # skip check attributes if it is tags
     return true if header_name == 'x-zammad-ticket-tags'
 
-    if header_name =~ /^x-zammad-(.+?)-(followup-|)(.*)$/i
+    if header_name =~ %r{^x-zammad-(.+?)-(followup-|)(.*)$}i
       class_name = $1
       attribute = $3
     end
@@ -401,7 +401,7 @@ returns
       data[:from_local]        = mail_address.local
       data[:from_domain]       = mail_address.domain
       data[:from_display_name] = mail_address.display_name || mail_address.comments&.first
-    elsif from =~ /^(.+?)<((.+?)@(.+?))>/
+    elsif from =~ %r{^(.+?)<((.+?)@(.+?))>}
       data[:from_email]        = $2
       data[:from_local]        = $3
       data[:from_domain]       = $4
@@ -419,7 +419,7 @@ returns
                  .to_s
                  .delete('"')
                  .strip
-                 .gsub(/(^'|'$)/, '')
+                 .gsub(%r{(^'|'$)}, '')
 
     data
   end
@@ -539,7 +539,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     part.body = force_japanese_encoding part.body.encoded.unpack1('M')
   end
 
-  ISO2022JP_REGEXP = /=\?ISO-2022-JP\?B\?(.+?)\?=/.freeze
+  ISO2022JP_REGEXP = %r{=\?ISO-2022-JP\?B\?(.+?)\?=}.freeze
 
   # https://github.com/zammad/zammad/issues/3115
   def header_field_unpack_japanese(field)
@@ -630,7 +630,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     return body_text if !options[:strict_html]
 
     # Issue #2390 - emails with >5k HTML links should be rejected
-    return EXCESSIVE_LINKS_MSG if body_text.scan(/<a[[:space:]]/i).count >= 5_000
+    return EXCESSIVE_LINKS_MSG if body_text.scan(%r{<a[[:space:]]}i).count >= 5_000
 
     body_text.html2html_strict
   end
@@ -717,7 +717,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     rescue
       begin
         case file.header[:content_disposition].to_s
-        when /(filename|name)(\*{0,1})="(.+?)"/i, /(filename|name)(\*{0,1})='(.+?)'/i, /(filename|name)(\*{0,1})=(.+?);/i
+        when %r{(filename|name)(\*{0,1})="(.+?)"}i, %r{(filename|name)(\*{0,1})='(.+?)'}i, %r{(filename|name)(\*{0,1})=(.+?);}i
           filename = $3
         end
       rescue
@@ -727,7 +727,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
 
     begin
       case file.header[:content_disposition].to_s
-      when /(filename|name)(\*{0,1})="(.+?)"/i, /(filename|name)(\*{0,1})='(.+?)'/i, /(filename|name)(\*{0,1})=(.+?);/i
+      when %r{(filename|name)(\*{0,1})="(.+?)"}i, %r{(filename|name)(\*{0,1})='(.+?)'}i, %r{(filename|name)(\*{0,1})=(.+?);}i
         filename = $3
       end
     rescue
@@ -737,7 +737,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     # as fallback, use raw values
     if filename.blank?
       case headers_store['Content-Disposition'].to_s
-      when /(filename|name)(\*{0,1})="(.+?)"/i, /(filename|name)(\*{0,1})='(.+?)'/i, /(filename|name)(\*{0,1})=(.+?);/i
+      when %r{(filename|name)(\*{0,1})="(.+?)"}i, %r{(filename|name)(\*{0,1})='(.+?)'}i, %r{(filename|name)(\*{0,1})=(.+?);}i
         filename = $3
       end
     end
@@ -767,7 +767,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     # e. g. Content-Type: video/quicktime; name="Video.MOV";
     if filename.blank?
       ['(filename|name)(\*{0,1})="(.+?)"(;|$)', '(filename|name)(\*{0,1})=\'(.+?)\'(;|$)', '(filename|name)(\*{0,1})=(.+?)(;|$)'].each do |regexp|
-        if headers_store['Content-Type'] =~ /#{regexp}/i
+        if headers_store['Content-Type'] =~ %r{#{regexp}}i
           filename = $3
           break
         end
@@ -785,7 +785,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     end
 
     # generate file name based on content-id with file extention
-    if filename.blank? && headers_store['Content-ID'].present? && headers_store['Content-ID'] =~ /(.+?\..{2,6})@.+?/i
+    if filename.blank? && headers_store['Content-ID'].present? && headers_store['Content-ID'] =~ %r{(.+?\..{2,6})@.+?}i
       filename = $1
     end
 
@@ -802,7 +802,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
         'image/gif':               %w[gif image],
       }
       map.each do |type, ext|
-        next if !content_type.match?(/^#{Regexp.quote(type)}/i)
+        next if !content_type.match?(%r{^#{Regexp.quote(type)}}i)
 
         filename = if headers_store['Content-Description'].present?
                      "#{headers_store['Content-Description']}.#{ext[0]}".to_s.force_encoding('utf-8')
@@ -814,7 +814,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     end
 
     # generate file name based on content-id without file extention
-    if filename.blank? && headers_store['Content-ID'].present? && headers_store['Content-ID'] =~ /(.+?)@.+?/i
+    if filename.blank? && headers_store['Content-ID'].present? && headers_store['Content-ID'] =~ %r{(.+?)@.+?}i
       filename = $1
     end
 
@@ -826,7 +826,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
     # create uniq filename
     local_filename = ''
     local_extention = ''
-    if filename =~ /^(.*?)\.(.+?)$/
+    if filename =~ %r{^(.*?)\.(.+?)$}
       local_filename = $1
       local_extention = $2
     end
@@ -925,7 +925,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
 
     reply.merge(
       to:            parsed_incoming_mail[:from_email],
-      body:          reply[:body].gsub(/\n/, "\r\n"),
+      body:          reply[:body].gsub(%r{\n}, "\r\n"),
       content_type:  'text/plain',
       References:    parsed_incoming_mail[:message_id],
       'In-Reply-To': parsed_incoming_mail[:message_id],
@@ -978,7 +978,7 @@ module Mail
       end
       return value if value.blank?
 
-      value.sub(/^.+?:(\s|)/, '')
+      value.sub(%r{^.+?:(\s|)}, '')
     end
   end
 
diff --git a/app/models/channel/filter/auto_response_check.rb b/app/models/channel/filter/auto_response_check.rb
index b22b9b80b..aaa4caf0d 100644
--- a/app/models/channel/filter/auto_response_check.rb
+++ b/app/models/channel/filter/auto_response_check.rb
@@ -15,17 +15,17 @@ module Channel::Filter::AutoResponseCheck
     mail[ :'x-zammad-article-preferences' ]['is-auto-response'] = true
 
     # do not send an auto response if one of the following headers exists
-    return if mail[ :'list-unsubscribe' ] && mail[ :'list-unsubscribe' ] =~ /.../
-    return if mail[ :'x-loop' ] && mail[ :'x-loop' ] =~ /(yes|true)/i
-    return if mail[ :precedence ] && mail[ :precedence ] =~ /(bulk|list|junk)/i
-    return if mail[ :'auto-submitted' ] && mail[ :'auto-submitted' ] =~ /auto-(generated|replied)/i
-    return if mail[ :'x-auto-response-suppress' ] && mail[ :'x-auto-response-suppress' ] =~ /all/i
+    return if mail[ :'list-unsubscribe' ] && mail[ :'list-unsubscribe' ] =~ %r{...}
+    return if mail[ :'x-loop' ] && mail[ :'x-loop' ] =~ %r{(yes|true)}i
+    return if mail[ :precedence ] && mail[ :precedence ] =~ %r{(bulk|list|junk)}i
+    return if mail[ :'auto-submitted' ] && mail[ :'auto-submitted' ] =~ %r{auto-(generated|replied)}i
+    return if mail[ :'x-auto-response-suppress' ] && mail[ :'x-auto-response-suppress' ] =~ %r{all}i
 
     # do not send an auto response if sender is system itself
     message_id = mail[ :message_id ]
     if message_id
       fqdn = Setting.get('fqdn')
-      return if message_id.match?(/@#{Regexp.quote(fqdn)}/i)
+      return if message_id.match?(%r{@#{Regexp.quote(fqdn)}}i)
     end
 
     mail[ :'x-zammad-send-auto-response' ] = true
diff --git a/app/models/channel/filter/bounce_delivery_permanent_failed.rb b/app/models/channel/filter/bounce_delivery_permanent_failed.rb
index b35addda2..4b384b93c 100644
--- a/app/models/channel/filter/bounce_delivery_permanent_failed.rb
+++ b/app/models/channel/filter/bounce_delivery_permanent_failed.rb
@@ -53,7 +53,7 @@ module Channel::Filter::BounceDeliveryPermanentFailed
       # get recipient bounce mail, mark this user to not sent notifications anymore
       final_recipient = mail[:mail_instance].final_recipient
       if final_recipient.present?
-        final_recipient.sub!(/rfc822;\s{0,10}/, '')
+        final_recipient.sub!(%r{rfc822;\s{0,10}}, '')
         if final_recipient.present?
           recipients.push final_recipient.downcase
         end
diff --git a/app/models/channel/filter/follow_up_check.rb b/app/models/channel/filter/follow_up_check.rb
index 3a5353afd..c20539a4c 100644
--- a/app/models/channel/filter/follow_up_check.rb
+++ b/app/models/channel/filter/follow_up_check.rb
@@ -72,7 +72,7 @@ module Channel::Filter::FollowUpCheck
         references += mail[:'in-reply-to']
       end
       if references != ''
-        message_ids = references.split(/\s+/)
+        message_ids = references.split(%r{\s+})
         message_ids.each do |message_id|
           message_id_md5 = Digest::MD5.hexdigest(message_id)
           article = Ticket::Article.where(message_id_md5: message_id_md5).order('created_at DESC, id DESC').limit(1).first
@@ -86,7 +86,7 @@ module Channel::Filter::FollowUpCheck
 
           # remove leading "..:\s" and "..[\d+]:\s" e. g. "Re: " or "Re[5]: "
           subject_to_check = mail[:subject]
-          subject_to_check.gsub!(/^(..(\[\d+\])?:\s+)+/, '')
+          subject_to_check.gsub!(%r{^(..(\[\d+\])?:\s+)+}, '')
 
           # if subject is different, it's no followup
           next if subject_to_check != article_first.subject
@@ -119,7 +119,7 @@ module Channel::Filter::FollowUpCheck
   def self.follow_up_by_md5(mail)
     return if mail[:'x-zammad-ticket-id']
 
-    mail_references(mail).split(/\s+/).each do |message_id|
+    mail_references(mail).split(%r{\s+}).each do |message_id|
       article = message_id_article(message_id)
       next if article.blank?
 
diff --git a/app/models/channel/filter/follow_up_possible_check.rb b/app/models/channel/filter/follow_up_possible_check.rb
index a1b1a6cd0..599f12f5a 100644
--- a/app/models/channel/filter/follow_up_possible_check.rb
+++ b/app/models/channel/filter/follow_up_possible_check.rb
@@ -8,7 +8,7 @@ module Channel::Filter::FollowUpPossibleCheck
 
     ticket = Ticket.lookup(id: ticket_id)
     return true if !ticket
-    return true if !ticket.state.state_type.name.match?(/^(closed|merged|removed)/i)
+    return true if !ticket.state.state_type.name.match?(%r{^(closed|merged|removed)}i)
 
     # in case of closed tickets, remove follow-up information
     case ticket.group.follow_up_possible
diff --git a/app/models/channel/filter/identify_sender.rb b/app/models/channel/filter/identify_sender.rb
index 7ec42123f..c5f4f50ab 100644
--- a/app/models/channel/filter/identify_sender.rb
+++ b/app/models/channel/filter/identify_sender.rb
@@ -123,10 +123,10 @@ module Channel::Filter::IdentifySender
         recipients.each do |recipient|
           address = nil
           display_name = nil
-          if recipient =~ /.*<(.+?)>/
+          if recipient =~ %r{.*<(.+?)>}
             address = $1
           end
-          if recipient =~ /^(.+?)<(.+?)>/
+          if recipient =~ %r{^(.+?)<(.+?)>}
             display_name = $1
           end
 
@@ -162,7 +162,7 @@ module Channel::Filter::IdentifySender
   end
 
   def self.populate_attributes!(attrs, **extras)
-    if attrs[:email].match?(/\S\s+\S/) || attrs[:email].match?(/^<|>$/)
+    if attrs[:email].match?(%r{\S\s+\S}) || attrs[:email].match?(%r{^<|>$})
       attrs[:preferences] = { mail_delivery_failed:        true,
                               mail_delivery_failed_reason: 'invalid email',
                               mail_delivery_failed_data:   Time.zone.now }
@@ -187,7 +187,7 @@ module Channel::Filter::IdentifySender
           .delete('"')
           .delete_prefix("'")
           .delete_suffix("'")
-          .gsub(/.+?\s\(.+?\)$/, '')
+          .gsub(%r{.+?\s\(.+?\)$}, '')
   end
 
   def self.sanitize_email(string)
@@ -197,10 +197,10 @@ module Channel::Filter::IdentifySender
           .strip
           .delete('"')
           .delete("'")
-          .delete(' ')             # see https://github.com/zammad/zammad/issues/2254
-          .sub(/^<|>$/, '')        # see https://github.com/zammad/zammad/issues/2254
-          .sub(/\A'(.*)'\z/, '\1') # see https://github.com/zammad/zammad/issues/2154
-          .gsub(/\s/, '')          # see https://github.com/zammad/zammad/issues/2198
+          .delete(' ') # see https://github.com/zammad/zammad/issues/2254
+          .sub(%r{^<|>$}, '')        # see https://github.com/zammad/zammad/issues/2254
+          .sub(%r{\A'(.*)'\z}, '\1') # see https://github.com/zammad/zammad/issues/2154
+          .gsub(%r{\s}, '')          # see https://github.com/zammad/zammad/issues/2198
           .delete_suffix('.')
   end
 
diff --git a/app/models/channel/filter/match/email_regex.rb b/app/models/channel/filter/match/email_regex.rb
index 846257211..a83ed1016 100644
--- a/app/models/channel/filter/match/email_regex.rb
+++ b/app/models/channel/filter/match/email_regex.rb
@@ -2,20 +2,20 @@ module Channel::Filter::Match::EmailRegex
 
   def self.match(value:, match_rule:, check_mode: false)
     regexp = false
-    if match_rule =~ /^(regex:)(.+?)$/
+    if match_rule =~ %r{^(regex:)(.+?)$}
       regexp = true
       match_rule = $2
     end
 
     if regexp == false
-      match_rule_quoted = Regexp.quote(match_rule).gsub(/\\\*/, '.*')
-      return true if value.match?(/#{match_rule_quoted}/i)
+      match_rule_quoted = Regexp.quote(match_rule).gsub(%r{\\\*}, '.*')
+      return true if value.match?(%r{#{match_rule_quoted}}i)
 
       return false
     end
 
     begin
-      return true if value.match?(/#{match_rule}/i)
+      return true if value.match?(%r{#{match_rule}}i)
 
       return false
     rescue => e
diff --git a/app/models/channel/filter/monitoring_base.rb b/app/models/channel/filter/monitoring_base.rb
index cc3ec66cc..f6e5e9604 100644
--- a/app/models/channel/filter/monitoring_base.rb
+++ b/app/models/channel/filter/monitoring_base.rb
@@ -47,26 +47,26 @@ class Channel::Filter::MonitoringBase
     return if result['host'].blank?
 
     # icinga - get state by body - new templates
-    if result['state'].blank? && mail[:body] =~ /.+?\sis\s(.+?)!/
+    if result['state'].blank? && mail[:body] =~ %r{.+?\sis\s(.+?)!}
       result['state'] = $1
     end
 
     # icinga - get state by subject - new templates "state:" is not in body anymore
     # Subject: [PROBLEM] Ping IPv4 on host1234.dc.example.com is WARNING!
     # Subject: [PROBLEM] Host host1234.dc.example.com is DOWN!
-    if result['state'].blank? && mail[:subject] =~ /(on|Host)\s.+?\sis\s(.+?)!/
+    if result['state'].blank? && mail[:subject] =~ %r{(on|Host)\s.+?\sis\s(.+?)!}
       result['state'] = $2
     end
 
     # monit - get missing attributes from body
-    if result['service'].blank? && mail[:body] =~ /\sService\s(.+?)\s/
+    if result['service'].blank? && mail[:body] =~ %r{\sService\s(.+?)\s}
       result['service'] = $1
     end
 
     # possible event types https://mmonit.com/monit/documentation/#Setting-an-event-filter
     if result['state'].blank?
       result['state'] = case mail[:body]
-                        when /\s(done|recovery|succeeded|bytes\sok|packets\sok)\s/, /(instance\schanged\snot|Link\sup|Exists|Saturation\sok|Speed\sok)/
+                        when %r{\s(done|recovery|succeeded|bytes\sok|packets\sok)\s}, %r{(instance\schanged\snot|Link\sup|Exists|Saturation\sok|Speed\sok)}
                           'OK'
                         else
                           'CRITICAL'
@@ -89,7 +89,7 @@ class Channel::Filter::MonitoringBase
       mail[ :'x-zammad-ticket-id' ] = ticket.id
 
       # check if service is recovered
-      if auto_close && result['state'].present? && result['state'].match(/#{state_recovery_match}/i)
+      if auto_close && result['state'].present? && result['state'].match(%r{#{state_recovery_match}}i)
         Rails.logger.info "MonitoringBase.#{integration} set autoclose to state_id #{auto_close_state_id}"
         state = Ticket::State.lookup(id: auto_close_state_id)
         if state
@@ -112,13 +112,13 @@ class Channel::Filter::MonitoringBase
     end
 
     # ignore states
-    if state_ignore_match.present? && result['state'].present? && result['state'].match(/#{state_ignore_match}/i)
+    if state_ignore_match.present? && result['state'].present? && result['state'].match(%r{#{state_ignore_match}}i)
       mail[ :'x-zammad-ignore' ] = true
       return true
     end
 
     # if now problem exists, just ignore the email
-    if result['state'].present? && result['state'].match(/#{state_recovery_match}/i)
+    if result['state'].present? && result['state'].match(%r{#{state_recovery_match}}i)
       mail[ :'x-zammad-ignore' ] = true
       return true
     end
diff --git a/app/models/channel/filter/out_of_office_check.rb b/app/models/channel/filter/out_of_office_check.rb
index 76f6f3334..3d964357d 100644
--- a/app/models/channel/filter/out_of_office_check.rb
+++ b/app/models/channel/filter/out_of_office_check.rb
@@ -8,7 +8,7 @@ module Channel::Filter::OutOfOfficeCheck
 
     # check ms out of office characteristics
     if mail[ :'x-auto-response-suppress' ]
-      return if !mail[ :'x-auto-response-suppress' ].match?(/all/i)
+      return if !mail[ :'x-auto-response-suppress' ].match?(%r{all}i)
       return if !mail[ :'x-ms-exchange-inbox-rules-loop' ]
 
       mail[ :'x-zammad-out-of-office' ] = true
@@ -18,17 +18,17 @@ module Channel::Filter::OutOfOfficeCheck
     if mail[ :'auto-submitted' ]
 
       # check zimbra out of office characteristics
-      if mail[ :'auto-submitted' ].match?(/vacation/i)
+      if mail[ :'auto-submitted' ].match?(%r{vacation}i)
         mail[ :'x-zammad-out-of-office' ] = true
       end
 
       # check cloud out of office characteristics
-      if mail[ :'auto-submitted' ].match?(/auto-replied;\sowner-email=/i)
+      if mail[ :'auto-submitted' ].match?(%r{auto-replied;\sowner-email=}i)
         mail[ :'x-zammad-out-of-office' ] = true
       end
 
       # gmail check out of office characteristics
-      if mail[ :'auto-submitted' ] =~ /auto-replied/i && mail[ :subject ] =~ /vacation/i
+      if mail[ :'auto-submitted' ] =~ %r{auto-replied}i && mail[ :subject ] =~ %r{vacation}i
         mail[ :'x-zammad-out-of-office' ] = true
       end
 
diff --git a/app/models/channel/filter/own_notification_loop_detection.rb b/app/models/channel/filter/own_notification_loop_detection.rb
index 086fe04c4..f7ed90b67 100644
--- a/app/models/channel/filter/own_notification_loop_detection.rb
+++ b/app/models/channel/filter/own_notification_loop_detection.rb
@@ -9,10 +9,10 @@ module Channel::Filter::OwnNotificationLoopDetection
 
     recedence = mail[:precedence]
     return if !recedence
-    return if !recedence.match?(/bulk/i)
+    return if !recedence.match?(%r{bulk}i)
 
     fqdn = Setting.get('fqdn')
-    return if !message_id.match?(/@#{Regexp.quote(fqdn)}>/i)
+    return if !message_id.match?(%r{@#{Regexp.quote(fqdn)}>}i)
 
     mail[ :'x-zammad-ignore' ] = true
     Rails.logger.info "Detected own sent notification mail and dropped it to prevent loops (message_id: #{message_id}, from: #{mail[:from]}, to: #{mail[:to]})"
diff --git a/app/models/channel/filter/service_now_check.rb b/app/models/channel/filter/service_now_check.rb
index 6ead40c3f..bc43823a6 100644
--- a/app/models/channel/filter/service_now_check.rb
+++ b/app/models/channel/filter/service_now_check.rb
@@ -44,7 +44,7 @@ returns:
 
     # check if we can find the service now relation
     source_id = nil
-    if subject =~ /\s(INC\d+)\s/
+    if subject =~ %r{\s(INC\d+)\s}
       source_id = $1
     end
 
diff --git a/app/models/channel/filter/trusted.rb b/app/models/channel/filter/trusted.rb
index a5bf57a20..9a2d4cc83 100644
--- a/app/models/channel/filter/trusted.rb
+++ b/app/models/channel/filter/trusted.rb
@@ -8,7 +8,7 @@ module Channel::Filter::Trusted
     # check if trust x-headers
     if !trusted(channel)
       mail.each_key do |key|
-        next if !key.match?(/^x-zammad/i)
+        next if !key.match?(%r{^x-zammad}i)
 
         mail.delete(key)
       end
@@ -17,7 +17,7 @@ module Channel::Filter::Trusted
 
     # verify values
     mail.each do |key, value|
-      next if !key.match?(/^x-zammad/i)
+      next if !key.match?(%r{^x-zammad}i)
 
       # no assoc exists, remove header
       next if Channel::EmailParser.check_attributes_by_x_headers(key, value)
diff --git a/app/models/chat.rb b/app/models/chat.rb
index 5c8069441..b1bb85a76 100644
--- a/app/models/chat.rb
+++ b/app/models/chat.rb
@@ -611,7 +611,7 @@ check if ip address is blocked for chat
     ips = block_ip.split(';')
     ips.each do |local_ip|
       return true if ip == local_ip.strip
-      return true if ip.match?(/#{local_ip.strip.gsub(/\*/, '.+?')}/)
+      return true if ip.match?(%r{#{local_ip.strip.gsub(%r{\*}, '.+?')}})
     end
     false
   end
diff --git a/app/models/concerns/can_clone_attachments.rb b/app/models/concerns/can_clone_attachments.rb
index 347ea22d4..4419db6f2 100644
--- a/app/models/concerns/can_clone_attachments.rb
+++ b/app/models/concerns/can_clone_attachments.rb
@@ -37,7 +37,7 @@ returns
       if options[:only_attached_attachments] == true && is_html_content == true
 
         content_id = new_attachment.preferences['Content-ID'] || new_attachment.preferences['content_id']
-        next if content_id.present? && body.present? && body.match?(/#{Regexp.quote(content_id)}/i)
+        next if content_id.present? && body.present? && body.match?(%r{#{Regexp.quote(content_id)}}i)
       end
 
       # only_inline_attachments mode is used when quoting HTML mail with #{article.body_as_html}
@@ -46,11 +46,11 @@ returns
         next if body.blank?
 
         content_disposition = new_attachment.preferences['Content-Disposition'] || new_attachment.preferences['content_disposition']
-        next if content_disposition.present? && content_disposition !~ /inline/
+        next if content_disposition.present? && content_disposition !~ %r{inline}
 
         content_id = new_attachment.preferences['Content-ID'] || new_attachment.preferences['content_id']
         next if content_id.blank?
-        next if !body.match?(/#{Regexp.quote(content_id)}/i)
+        next if !body.match?(%r{#{Regexp.quote(content_id)}}i)
       end
 
       already_added = false
diff --git a/app/models/concerns/checks_client_notification.rb b/app/models/concerns/checks_client_notification.rb
index 85862c6bc..25b9e5716 100644
--- a/app/models/concerns/checks_client_notification.rb
+++ b/app/models/concerns/checks_client_notification.rb
@@ -12,7 +12,7 @@ module ChecksClientNotification
 
   def notify_clients_data(event)
     class_name = self.class.name
-    class_name.gsub!(/::/, '')
+    class_name.gsub!(%r{::}, '')
 
     {
       message: {
diff --git a/app/models/concerns/has_rich_text.rb b/app/models/concerns/has_rich_text.rb
index 7015239c5..e4fd1d30c 100644
--- a/app/models/concerns/has_rich_text.rb
+++ b/app/models/concerns/has_rich_text.rb
@@ -58,7 +58,7 @@ Checks if file is used inline
 
         node.remove
       when 'div'
-        node.children.to_a.select { |t| t.text.match?(/\A([\n\r]+)\z/) }.each(&:remove)
+        node.children.to_a.select { |t| t.text.match?(%r{\A([\n\r]+)\z}) }.each(&:remove)
 
         node.remove if node.children.none? && node.classes.none?
       end
@@ -138,7 +138,7 @@ Checks if file is used inline
         next if node.name != 'img'
         next if !node['src']&.start_with?('cid:')
 
-        cid = node['src'].sub(/^cid:/, '')
+        cid = node['src'].sub(%r{^cid:}, '')
         lookup_cids = [cid, "<#{cid}>"]
 
         attachment = attachments.find do |file|
@@ -164,7 +164,7 @@ Checks if file is used inline
         next if node.name != 'img'
         next if !node['src']&.start_with? 'cid:'
 
-        cid = node['src'].sub(/^cid:/, '')
+        cid = node['src'].sub(%r{^cid:}, '')
         inline_cids << cid
       end
 
diff --git a/app/models/cti/caller_id.rb b/app/models/cti/caller_id.rb
index e865b08b8..583dae415 100644
--- a/app/models/cti/caller_id.rb
+++ b/app/models/cti/caller_id.rb
@@ -226,19 +226,19 @@ returns
       # see specs for example
       return [] if !text.is_a?(String)
 
-      text.scan(/([\d\s\-(|)]{6,26})/).map do |match|
+      text.scan(%r{([\d\s\-(|)]{6,26})}).map do |match|
         normalize_number(match[0])
       end
     end
 
     def self.normalize_number(number)
-      number = number.gsub(/[\s-]/, '')
-      number.gsub!(/^(00)?(\+?\d\d)\(0?(\d*)\)/, '\\1\\2\\3')
-      number.gsub!(/\D/, '')
+      number = number.gsub(%r{[\s-]}, '')
+      number.gsub!(%r{^(00)?(\+?\d\d)\(0?(\d*)\)}, '\\1\\2\\3')
+      number.gsub!(%r{\D}, '')
       case number
-      when /^00/
+      when %r{^00}
         number[2..]
-      when /^0/
+      when %r{^0}
         DEFAULT_COUNTRY_ID + number[1..]
       else
         number
diff --git a/app/models/cti/driver/base.rb b/app/models/cti/driver/base.rb
index f378463a3..4e796d49a 100644
--- a/app/models/cti/driver/base.rb
+++ b/app/models/cti/driver/base.rb
@@ -97,8 +97,8 @@ class Cti::Driver::Base
 
     if routing_table.present?
       routing_table.each do |row|
-        dest = row[:dest].gsub(/\*/, '.+?')
-        next if !to.match?(/^#{dest}$/)
+        dest = row[:dest].gsub(%r{\*}, '.+?')
+        next if !to.match?(%r{^#{dest}$})
 
         return {
           action: 'set_caller_id',
diff --git a/app/models/cti/log.rb b/app/models/cti/log.rb
index 21fdc64c3..6b8a5d178 100644
--- a/app/models/cti/log.rb
+++ b/app/models/cti/log.rb
@@ -6,7 +6,7 @@ module Cti
 
     store :preferences, accessors: %i[from_pretty to_pretty]
 
-    validates :state, format: { with: /\A(newCall|answer|hangup)\z/,  message: 'newCall|answer|hangup is allowed' }
+    validates :state, format: { with: %r{\A(newCall|answer|hangup)\z},  message: 'newCall|answer|hangup is allowed' }
 
     before_create :set_pretty
     before_update :set_pretty
@@ -506,7 +506,7 @@ optional you can put the max oldest chat entries as argument
 
     def set_pretty
       %i[from to].each do |field|
-        parsed = TelephoneNumber.parse(send(field)&.sub(/^\+?/, '+'))
+        parsed = TelephoneNumber.parse(send(field)&.sub(%r{^\+?}, '+'))
         preferences[:"#{field}_pretty"] = parsed.send(parsed.valid? ? :international_number : :original_number)
       end
     end
diff --git a/app/models/job.rb b/app/models/job.rb
index d7982bbc0..496182b52 100644
--- a/app/models/job.rb
+++ b/app/models/job.rb
@@ -264,7 +264,7 @@ job.run(true)
   def match_minutes(minutes)
     return 0 if minutes < 10
 
-    "#{minutes.to_s.gsub(/(\d)\d/, '\\1')}0".to_i
+    "#{minutes.to_s.gsub(%r{(\d)\d}, '\\1')}0".to_i
   end
 
 end
diff --git a/app/models/object_manager/attribute.rb b/app/models/object_manager/attribute.rb
index 969531957..9f4e5054e 100644
--- a/app/models/object_manager/attribute.rb
+++ b/app/models/object_manager/attribute.rb
@@ -569,22 +569,22 @@ to send no browser reload event, pass false
 
       data_type = nil
       case attribute.data_type
-      when /^input|select|tree_select|richtext|textarea|checkbox$/
+      when %r{^input|select|tree_select|richtext|textarea|checkbox$}
         data_type = :string
-      when /^integer|user_autocompletion$/
+      when %r{^integer|user_autocompletion$}
         data_type = :integer
-      when /^boolean|active$/
+      when %r{^boolean|active$}
         data_type = :boolean
-      when /^datetime$/
+      when %r{^datetime$}
         data_type = :datetime
-      when /^date$/
+      when %r{^date$}
         data_type = :date
       end
 
       # change field
       if model.column_names.include?(attribute.name)
         case attribute.data_type
-        when /^input|select|tree_select|richtext|textarea|checkbox$/
+        when %r{^input|select|tree_select|richtext|textarea|checkbox$}
           ActiveRecord::Migration.change_column(
             model.table_name,
             attribute.name,
@@ -592,7 +592,7 @@ to send no browser reload event, pass false
             limit: attribute.data_option[:maxlength],
             null:  true
           )
-        when /^integer|user_autocompletion|datetime|date$/, /^boolean|active$/
+        when %r{^integer|user_autocompletion|datetime|date$}, %r{^boolean|active$}
           ActiveRecord::Migration.change_column(
             model.table_name,
             attribute.name,
@@ -616,7 +616,7 @@ to send no browser reload event, pass false
 
       # create field
       case attribute.data_type
-      when /^input|select|tree_select|richtext|textarea|checkbox$/
+      when %r{^input|select|tree_select|richtext|textarea|checkbox$}
         ActiveRecord::Migration.add_column(
           model.table_name,
           attribute.name,
@@ -624,7 +624,7 @@ to send no browser reload event, pass false
           limit: attribute.data_option[:maxlength],
           null:  true
         )
-      when /^integer|user_autocompletion$/, /^boolean|active$/, /^datetime|date$/
+      when %r{^integer|user_autocompletion$}, %r{^boolean|active$}, %r{^datetime|date$}
         ActiveRecord::Migration.add_column(
           model.table_name,
           attribute.name,
@@ -780,22 +780,22 @@ is certain attribute used by triggers, overviews or schedulers
   def check_name
     return if !name
 
-    if name.match?(/.+?_(id|ids)$/i)
+    if name.match?(%r{.+?_(id|ids)$}i)
       errors.add(:name, "can't get used because *_id and *_ids are not allowed")
     end
-    if name.match?(/\s/)
+    if name.match?(%r{\s})
       errors.add(:name, 'spaces are not allowed')
     end
-    if !name.match?(/^[a-z0-9_]+$/)
+    if !name.match?(%r{^[a-z0-9_]+$})
       errors.add(:name, 'Only letters from a-z because numbers from 0-9 and _ are allowed')
     end
-    if !name.match?(/[a-z]/)
+    if !name.match?(%r{[a-z]})
       errors.add(:name, 'At least one letters is needed')
     end
 
     # do not allow model method names as attributes
     reserved_words = %w[destroy true false integer select drop create alter index table varchar blob date datetime timestamp url icon initials avatar permission validate subscribe unsubscribe translate search _type _doc _id id]
-    if name.match?(/^(#{reserved_words.join('|')})$/)
+    if name.match?(%r{^(#{reserved_words.join('|')})$})
       errors.add(:name, "#{name} is a reserved word! (1)")
     end
 
@@ -833,7 +833,7 @@ is certain attribute used by triggers, overviews or schedulers
     local_data_option[:null] = true if local_data_option[:null].nil?
 
     case data_type
-    when /^((tree_)?select|checkbox)$/
+    when %r{^((tree_)?select|checkbox)$}
       local_data_option[:nulloption] = true if local_data_option[:nulloption].nil?
       local_data_option[:maxlength] ||= 255
     end
@@ -882,17 +882,17 @@ is certain attribute used by triggers, overviews or schedulers
     when 'input'
       [{ failed:  %w[text password tel fax email url].exclude?(local_data_option[:type]),
          message: 'must have one of text/password/tel/fax/email/url for :type' },
-       { failed:  !local_data_option[:maxlength].to_s.match?(/^\d+$/),
+       { failed:  !local_data_option[:maxlength].to_s.match?(%r{^\d+$}),
          message: 'must have integer for :maxlength' }]
     when 'richtext'
-      [{ failed:  !local_data_option[:maxlength].to_s.match?(/^\d+$/),
+      [{ failed:  !local_data_option[:maxlength].to_s.match?(%r{^\d+$}),
          message: 'must have integer for :maxlength' }]
     when 'integer'
-      [{ failed:  !local_data_option[:min].to_s.match?(/^\d+$/),
+      [{ failed:  !local_data_option[:min].to_s.match?(%r{^\d+$}),
          message: 'must have integer for :min' },
-       { failed:  !local_data_option[:max].to_s.match?(/^\d+$/),
+       { failed:  !local_data_option[:max].to_s.match?(%r{^\d+$}),
          message: 'must have integer for :max' }]
-    when /^((tree_)?select|checkbox)$/
+    when %r{^((tree_)?select|checkbox)$}
       [{ failed:  !local_data_option.key?(:default),
          message: 'must have value for :default' },
        { failed:  local_data_option[:options].nil? && local_data_option[:relation].nil?,
diff --git a/app/models/organization.rb b/app/models/organization.rb
index 9ac1ce3a8..b0afaefcf 100644
--- a/app/models/organization.rb
+++ b/app/models/organization.rb
@@ -38,8 +38,8 @@ class Organization < ApplicationModel
   def domain_cleanup
     return true if domain.blank?
 
-    domain.gsub!(/@/, '')
-    domain.gsub!(/\s*/, '')
+    domain.gsub!(%r{@}, '')
+    domain.gsub!(%r{\s*}, '')
     domain.strip!
     domain.downcase!
     true
diff --git a/app/models/overview.rb b/app/models/overview.rb
index d3f119b5f..2a3a6b209 100644
--- a/app/models/overview.rb
+++ b/app/models/overview.rb
@@ -98,7 +98,7 @@ class Overview < ApplicationModel
   def link_name(name)
     local_link = name.downcase
     local_link = local_link.parameterize(separator: '_')
-    local_link.gsub!(/\s/, '_')
+    local_link.gsub!(%r{\s}, '_')
     local_link.squeeze!('_')
     local_link = CGI.escape(local_link)
     if local_link.blank?
diff --git a/app/models/package.rb b/app/models/package.rb
index 98e333f22..8fe84021b 100644
--- a/app/models/package.rb
+++ b/app/models/package.rb
@@ -64,7 +64,7 @@ install all packages located under auto_install/*.zpm
 
     data = []
     Dir.foreach(path) do |entry|
-      if entry.include?('.zpm') && entry !~ /^\./
+      if entry.include?('.zpm') && entry !~ %r{^\.}
         data.push entry
       end
     end
@@ -133,7 +133,7 @@ execute migration down + unlink files
     Dir.glob("#{package_base_dir}/**/*") do |entry|
       entry = entry.sub('//', '/')
       file = entry
-      file = file.sub(/#{package_base_dir}/, '')
+      file = file.sub(%r{#{package_base_dir}}, '')
       dest = "#{@@root}/#{file}"
 
       if File.symlink?(dest.to_s)
@@ -166,7 +166,7 @@ link files + execute migration up
     Dir.glob("#{package_base_dir}/**/*") do |entry|
       entry = entry.sub('//', '/')
       file = entry
-      file = file.sub(/#{package_base_dir}/, '')
+      file = file.sub(%r{#{package_base_dir}}, '')
       file = file.sub(%r{^/}, '')
 
       # ignore files
diff --git a/app/models/package/migration.rb b/app/models/package/migration.rb
index 5d3689435..6dbeeeb82 100644
--- a/app/models/package/migration.rb
+++ b/app/models/package/migration.rb
@@ -41,7 +41,7 @@ class Package::Migration < ApplicationModel
 
       version = nil
       name    = nil
-      if migration =~ /^(.+?)_(.*)\.rb$/
+      if migration =~ %r{^(.+?)_(.*)\.rb$}
         version = $1
         name    = $2
       end
diff --git a/app/models/postmaster_filter.rb b/app/models/postmaster_filter.rb
index da110f1a4..3116bfa8c 100644
--- a/app/models/postmaster_filter.rb
+++ b/app/models/postmaster_filter.rb
@@ -12,7 +12,7 @@ class PostmasterFilter < ApplicationModel
     raise Exceptions::UnprocessableEntity, 'Min. one match rule needed!' if match.blank?
 
     match.each_value do |meta|
-      raise Exceptions::UnprocessableEntity, 'operator invalid, ony "contains" and "contains not" is supported' if meta['operator'].blank? || meta['operator'] !~ /^(contains|contains not)$/
+      raise Exceptions::UnprocessableEntity, 'operator invalid, ony "contains" and "contains not" is supported' if meta['operator'].blank? || meta['operator'] !~ %r{^(contains|contains not)$}
       raise Exceptions::UnprocessableEntity, 'value invalid/empty' if meta['value'].blank?
 
       begin
diff --git a/app/models/setting.rb b/app/models/setting.rb
index a3a2658f5..46094e8da 100644
--- a/app/models/setting.rb
+++ b/app/models/setting.rb
@@ -120,7 +120,7 @@ reload config settings
           @@current[key] = value
           next
         end
-        @@current[key] = value.gsub(/\#\{config\.(.+?)\}/) do
+        @@current[key] = value.gsub(%r{\#\{config\.(.+?)\}}) do
           @@raw[$1].to_s
         end
       end
diff --git a/app/models/smime_certificate.rb b/app/models/smime_certificate.rb
index ed9efcaef..d121fc1fb 100644
--- a/app/models/smime_certificate.rb
+++ b/app/models/smime_certificate.rb
@@ -4,7 +4,7 @@ class SMIMECertificate < ApplicationModel
   validates :fingerprint, uniqueness: true
 
   def self.parse(raw)
-    OpenSSL::X509::Certificate.new(raw.gsub(/(?:TRUSTED\s)?(CERTIFICATE---)/, '\1'))
+    OpenSSL::X509::Certificate.new(raw.gsub(%r{(?:TRUSTED\s)?(CERTIFICATE---)}, '\1'))
   end
 
   # Search for the certificate of the given sender email address
@@ -94,7 +94,7 @@ class SMIMECertificate < ApplicationModel
 
   def email_addresses_from_subject_alt_name(subject_alt_name)
     # ["IP Address:192.168.7.23", "IP Address:192.168.7.42", "email:jd@example.com", "email:John.Doe@example.com", "dirName:dir_sect"]
-    entries = subject_alt_name.value.split(/,\s?/)
+    entries = subject_alt_name.value.split(%r{,\s?})
 
     entries.each_with_object([]) do |entry, result|
       # ["email:jd@example.com", "email:John.Doe@example.com"]
diff --git a/app/models/text_module.rb b/app/models/text_module.rb
index 024b82850..9dc3c53cb 100644
--- a/app/models/text_module.rb
+++ b/app/models/text_module.rb
@@ -114,9 +114,9 @@ push text_modules to online
 
   def validate_content
     return true if content.blank?
-    return true if content.match?(/<.+?>/)
+    return true if content.match?(%r{<.+?>})
 
-    content.gsub!(/(\r\n|\n\r|\r)/, "\n")
+    content.gsub!(%r{(\r\n|\n\r|\r)}, "\n")
     self.content = content.text2html
     true
   end
diff --git a/app/models/ticket.rb b/app/models/ticket.rb
index c2519b245..04d0b50e7 100644
--- a/app/models/ticket.rb
+++ b/app/models/ticket.rb
@@ -627,7 +627,7 @@ condition example
 
       selector = selector_raw.stringify_keys
       raise "Invalid selector, operator missing #{selector.inspect}" if !selector['operator']
-      raise "Invalid selector, operator #{selector['operator']} is invalid #{selector.inspect}" if !selector['operator'].match?(/^(is|is\snot|contains|contains\s(not|all|one|all\snot|one\snot)|(after|before)\s\(absolute\)|(within\snext|within\slast|after|before|till|from)\s\(relative\))|(is\sin\sworking\stime|is\snot\sin\sworking\stime)$/)
+      raise "Invalid selector, operator #{selector['operator']} is invalid #{selector.inspect}" if !selector['operator'].match?(%r{^(is|is\snot|contains|contains\s(not|all|one|all\snot|one\snot)|(after|before)\s\(absolute\)|(within\snext|within\slast|after|before|till|from)\s\(relative\))|(is\sin\sworking\stime|is\snot\sin\sworking\stime)$})
 
       # validate value / allow blank but only if pre_condition exists and is not specific
       if !selector.key?('value') ||
@@ -639,7 +639,7 @@ condition example
       end
 
       # validate pre_condition values
-      return nil if selector['pre_condition'] && selector['pre_condition'] !~ /^(not_set|current_user\.|specific)/
+      return nil if selector['pre_condition'] && selector['pre_condition'] !~ %r{^(not_set|current_user\.|specific)}
 
       # get attributes
       attributes = attribute.split('.')
@@ -699,7 +699,7 @@ condition example
 
       if selector['operator'] == 'is'
         if selector['pre_condition'] == 'not_set'
-          if attributes[1].match?(/^(created_by|updated_by|owner|customer|user)_id/)
+          if attributes[1].match?(%r{^(created_by|updated_by|owner|customer|user)_id})
             query += "(#{attribute} IS NULL OR #{attribute} IN (?))"
             bind_params.push 1
           else
@@ -744,7 +744,7 @@ condition example
         end
       elsif selector['operator'] == 'is not'
         if selector['pre_condition'] == 'not_set'
-          if attributes[1].match?(/^(created_by|updated_by|owner|customer|user)_id/)
+          if attributes[1].match?(%r{^(created_by|updated_by|owner|customer|user)_id})
             query += "(#{attribute} IS NOT NULL AND #{attribute} NOT IN (?))"
             bind_params.push 1
           else
@@ -1444,7 +1444,7 @@ result
   def check_title
     return true if !title
 
-    title.gsub!(/\s|\t|\r/, ' ')
+    title.gsub!(%r{\s|\t|\r}, ' ')
     true
   end
 
@@ -1476,7 +1476,7 @@ result
     current_state_type = Ticket::StateType.lookup(id: current_state.state_type_id)
 
     # in case, set pending_time to nil
-    return true if current_state_type.name.match?(/^pending/i)
+    return true if current_state_type.name.match?(%r{^pending}i)
 
     self.pending_time = nil
     true
@@ -1561,7 +1561,7 @@ result
         User.group_access(group_id, 'full').sort_by(&:login).each do |user|
           recipients_raw.push(user.email)
         end
-      when /\Auserid_(\d+)\z/
+      when %r{\Auserid_(\d+)\z}
         user = User.lookup(id: $1)
         if !user
           logger.warn "Can't find configured Trigger Email recipient User with ID '#{$1}'"
@@ -1592,7 +1592,7 @@ result
         end
       rescue
         if recipient_email.present?
-          if recipient_email !~ /^(.+?)<(.+?)@(.+?)>$/
+          if recipient_email !~ %r{^(.+?)<(.+?)@(.+?)>$}
             next # no usable format found
           end
 
@@ -1609,15 +1609,15 @@ result
       # do not sent notifications to this recipients
       send_no_auto_response_reg_exp = Setting.get('send_no_auto_response_reg_exp')
       begin
-        next if recipient_email.match?(/#{send_no_auto_response_reg_exp}/i)
+        next if recipient_email.match?(%r{#{send_no_auto_response_reg_exp}}i)
       rescue => e
         logger.error "Invalid regex '#{send_no_auto_response_reg_exp}' in setting send_no_auto_response_reg_exp"
         logger.error e
-        next if recipient_email.match?(/(mailer-daemon|postmaster|abuse|root|noreply|noreply.+?|no-reply|no-reply.+?)@.+?/i)
+        next if recipient_email.match?(%r{(mailer-daemon|postmaster|abuse|root|noreply|noreply.+?|no-reply|no-reply.+?)@.+?}i)
       end
 
       # check if notification should be send because of customer emails
-      if article.present? && article.preferences.fetch('is-auto-response', false) == true && article.from && article.from =~ /#{Regexp.quote(recipient_email)}/i
+      if article.present? && article.preferences.fetch('is-auto-response', false) == true && article.from && article.from =~ %r{#{Regexp.quote(recipient_email)}}i
         logger.info "Send no trigger based notification to #{recipient_email} because of auto response tagged incoming email"
         next
       end
@@ -1812,7 +1812,7 @@ result
       owner_id
     when 'ticket_agents'
       User.group_access(group_id, 'full').sort_by(&:login)
-    when /\Auserid_(\d+)\z/
+    when %r{\Auserid_(\d+)\z}
       return $1 if User.exists?($1)
 
       logger.warn "Can't find configured Trigger SMS recipient User with ID '#{$1}'"
diff --git a/app/models/ticket/article.rb b/app/models/ticket/article.rb
index 80429d63b..b9bb81ae4 100644
--- a/app/models/ticket/article.rb
+++ b/app/models/ticket/article.rb
@@ -85,10 +85,10 @@ returns
   def self.insert_urls(article)
     return article if article['attachments'].blank?
     return article if !article['content_type'].match?(%r{text/html}i)
-    return article if article['body'] !~ /<img/i
+    return article if article['body'] !~ %r{<img}i
 
     inline_attachments = {}
-    article['body'].gsub!( /(<img[[:space:]](|.+?)src=")cid:(.+?)"(|.+?)>/im ) do |item|
+    article['body'].gsub!( %r{(<img[[:space:]](|.+?)src=")cid:(.+?)"(|.+?)>}im ) do |item|
       tag_start = $1
       cid = $3
       tag_end = $4
@@ -129,7 +129,7 @@ returns
 
   def attachments_inline
     inline_attachments = {}
-    body.gsub( /<img[[:space:]](|.+?)src="cid:(.+?)"(|.+?)>/im ) do |_item|
+    body.gsub( %r{<img[[:space:]](|.+?)src="cid:(.+?)"(|.+?)>}im ) do |_item|
       cid = $2
 
       # look for attachment
@@ -251,7 +251,7 @@ returns:
     return true if attribute != :body
     return false if content_type.blank?
 
-    content_type =~ /html/i
+    content_type =~ %r{html}i
   end
 
 =begin
@@ -306,7 +306,7 @@ returns
   def check_subject
     return true if subject.blank?
 
-    subject.gsub!(/\s|\t|\r/, ' ')
+    subject.gsub!(%r{\s|\t|\r}, ' ')
     true
   end
 
diff --git a/app/models/ticket/article/enqueue_communicate_telegram_job.rb b/app/models/ticket/article/enqueue_communicate_telegram_job.rb
index ba24a4599..d896970eb 100644
--- a/app/models/ticket/article/enqueue_communicate_telegram_job.rb
+++ b/app/models/ticket/article/enqueue_communicate_telegram_job.rb
@@ -26,7 +26,7 @@ module Ticket::Article::EnqueueCommunicateTelegramJob
     return true if !type_id
 
     type = Ticket::Article::Type.lookup(id: type_id)
-    return true if !type.name.match?(/\Atelegram/i)
+    return true if !type.name.match?(%r{\Atelegram}i)
 
     CommunicateTelegramJob.perform_later(id)
   end
diff --git a/app/models/ticket/article/enqueue_communicate_twitter_job.rb b/app/models/ticket/article/enqueue_communicate_twitter_job.rb
index 2c55ba376..5c37f722c 100644
--- a/app/models/ticket/article/enqueue_communicate_twitter_job.rb
+++ b/app/models/ticket/article/enqueue_communicate_twitter_job.rb
@@ -31,7 +31,7 @@ module Ticket::Article::EnqueueCommunicateTwitterJob
 
     type = Ticket::Article::Type.lookup(id: type_id)
     return true if type.nil?
-    return true if !type.name.match?(/\Atwitter/i)
+    return true if !type.name.match?(%r{\Atwitter}i)
 
     raise Exceptions::UnprocessableEntity, 'twitter to: parameter is missing' if to.blank? && type['name'] == 'twitter direct-message'
 
diff --git a/app/models/ticket/number/date.rb b/app/models/ticket/number/date.rb
index 5f1f3338b..7a44d9645 100644
--- a/app/models/ticket/number/date.rb
+++ b/app/models/ticket/number/date.rb
@@ -40,12 +40,12 @@ module Ticket::Number::Date
     # probe format
     # NOTE: we use `(?<=\W|^)` at the start of the regular expressions below
     # because `\b` fails when ticket_hook begins with a non-word character (like '#')
-    string.scan(/(?<=\W|^)#{Regexp.quote(ticket_hook)}#{Regexp.quote(ticket_hook_divider)}(\d{4,10}#{system_id}\d{2,40})\b/i) do
+    string.scan(%r{(?<=\W|^)#{Regexp.quote(ticket_hook)}#{Regexp.quote(ticket_hook_divider)}(\d{4,10}#{system_id}\d{2,40})\b}i) do
       ticket = Ticket.find_by(number: $1)
       break if ticket
     end
     if !ticket
-      string.scan(/(?<=\W|^)#{Regexp.quote(ticket_hook)}\s{0,2}(\d{4,10}#{system_id}\d{2,40})\b/i) do
+      string.scan(%r{(?<=\W|^)#{Regexp.quote(ticket_hook)}\s{0,2}(\d{4,10}#{system_id}\d{2,40})\b}i) do
         ticket = Ticket.find_by(number: $1)
         break if ticket
       end
diff --git a/app/models/ticket/number/increment.rb b/app/models/ticket/number/increment.rb
index 0db856caf..96747ee91 100644
--- a/app/models/ticket/number/increment.rb
+++ b/app/models/ticket/number/increment.rb
@@ -38,13 +38,13 @@ module Ticket::Number::Increment
     # probe format
     # NOTE: we use `(?<=\W|^)` at the start of the regular expressions below
     # because `\b` fails when ticket_hook begins with a non-word character (like '#')
-    string.scan(/(?<=\W|^)#{Regexp.quote(ticket_hook)}#{Regexp.quote(ticket_hook_divider)}(#{system_id}\d{2,48})\b/i) do
+    string.scan(%r{(?<=\W|^)#{Regexp.quote(ticket_hook)}#{Regexp.quote(ticket_hook_divider)}(#{system_id}\d{2,48})\b}i) do
       ticket = Ticket.find_by(number: $1)
       break if ticket
     end
 
     if !ticket
-      string.scan(/(?<=\W|^)#{Regexp.quote(ticket_hook)}\s{0,2}(#{system_id}\d{2,48})\b/i) do
+      string.scan(%r{(?<=\W|^)#{Regexp.quote(ticket_hook)}\s{0,2}(#{system_id}\d{2,48})\b}i) do
         ticket = Ticket.find_by(number: $1)
         break if ticket
       end
diff --git a/app/models/ticket/overviews.rb b/app/models/ticket/overviews.rb
index 7e7072213..a24627a41 100644
--- a/app/models/ticket/overviews.rb
+++ b/app/models/ticket/overviews.rb
@@ -103,7 +103,7 @@ returns
       order_by = overview.order[:by]
 
       # validate direction
-      raise "Invalid order direction '#{direction}'" if direction && direction !~ /^(ASC|DESC)$/i
+      raise "Invalid order direction '#{direction}'" if direction && direction !~ %r{^(ASC|DESC)$}i
 
       # check if order by exists
       if !ticket_attributes.key?(order_by)
diff --git a/app/models/ticket/search_index.rb b/app/models/ticket/search_index.rb
index c33a91805..2aa3b51a9 100644
--- a/app/models/ticket/search_index.rb
+++ b/app/models/ticket/search_index.rb
@@ -98,7 +98,7 @@ module Ticket::SearchIndex
     return true if attachment.filename.blank?
 
     filename_extention = attachment.filename.downcase
-    filename_extention.gsub!(/^.*(\..+?)$/, '\\1')
+    filename_extention.gsub!(%r{^.*(\..+?)$}, '\\1')
 
     # list ignored file extensions
     attachments_ignore = Setting.get('es_attachment_ignore') || [ '.png', '.jpg', '.jpeg', '.mpeg', '.mpg', '.mov', '.bin', '.exe' ]
diff --git a/app/models/ticket/subject.rb b/app/models/ticket/subject.rb
index 802b688c2..0d85481c8 100644
--- a/app/models/ticket/subject.rb
+++ b/app/models/ticket/subject.rb
@@ -57,17 +57,17 @@ returns
     ticket_subject_size = Setting.get('ticket_subject_size')
 
     # remove all possible ticket hook formats with []
-    subject = subject.gsub(/\[#{ticket_hook}: #{number}\](\s+?|)/, '')
-    subject = subject.gsub(/\[#{ticket_hook}:#{number}\](\s+?|)/, '')
-    subject = subject.gsub(/\[#{ticket_hook}#{ticket_hook_divider}#{number}\](\s+?|)/, '')
+    subject = subject.gsub(%r{\[#{ticket_hook}: #{number}\](\s+?|)}, '')
+    subject = subject.gsub(%r{\[#{ticket_hook}:#{number}\](\s+?|)}, '')
+    subject = subject.gsub(%r{\[#{ticket_hook}#{ticket_hook_divider}#{number}\](\s+?|)}, '')
 
     # remove all possible ticket hook formats without []
-    subject = subject.gsub(/#{ticket_hook}: #{number}(\s+?|)/, '')
-    subject = subject.gsub(/#{ticket_hook}:#{number}(\s+?|)/, '')
-    subject = subject.gsub(/#{ticket_hook}#{ticket_hook_divider}#{number}(\s+?|)/, '')
+    subject = subject.gsub(%r{#{ticket_hook}: #{number}(\s+?|)}, '')
+    subject = subject.gsub(%r{#{ticket_hook}:#{number}(\s+?|)}, '')
+    subject = subject.gsub(%r{#{ticket_hook}#{ticket_hook_divider}#{number}(\s+?|)}, '')
 
     # remove leading "..:\s" and "..[\d+]:\s" e. g. "Re: " or "Re[5]: "
-    subject = subject.gsub(/^(..(\[\d+\])?:\s)+/, '')
+    subject = subject.gsub(%r{^(..(\[\d+\])?:\s)+}, '')
 
     # resize subject based on config
     if subject.length > ticket_subject_size.to_i
diff --git a/app/models/transaction/slack.rb b/app/models/transaction/slack.rb
index 9225247a1..268574941 100644
--- a/app/models/transaction/slack.rb
+++ b/app/models/transaction/slack.rb
@@ -106,7 +106,7 @@ class Transaction::Slack
       if ticket.pending_time && ticket.pending_time < Time.zone.now
         color = '#faab00'
       end
-    elsif ticket_state_type.match?(/^(new|open)$/)
+    elsif ticket_state_type.match?(%r{^(new|open)$})
       color = '#faab00'
     elsif ticket_state_type == 'closed'
       color = '#38ad69'
diff --git a/app/models/translation.rb b/app/models/translation.rb
index 53260d211..8431e1071 100644
--- a/app/models/translation.rb
+++ b/app/models/translation.rb
@@ -416,7 +416,7 @@ Get source file at https://i18n.zammad.com/api/v1/translations_empty_translation
         next
       end
       raise "Can't import translation, format is missing" if row[2].blank?
-      raise "Can't import translation, format is invalid (#{row[2]})" if !row[2].match?(/^(time|string)$/)
+      raise "Can't import translation, format is invalid (#{row[2]})" if !row[2].match?(%r{^(time|string)$})
 
       item = {
         'locale'         => locale.locale,
diff --git a/app/models/user.rb b/app/models/user.rb
index 8eb1421e0..167855710 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -841,7 +841,7 @@ try to find correct name
     end
 
     # "Firstname Lastname"
-    if string =~ /^(((Dr\.|Prof\.)[[:space:]]|).+?)[[:space:]](.+?)$/i
+    if string =~ %r{^(((Dr\.|Prof\.)[[:space:]]|).+?)[[:space:]](.+?)$}i
       if $1.present?
         firstname = $1.strip
       end
@@ -853,7 +853,7 @@ try to find correct name
 
     # -no name- "firstname.lastname@example.com"
     if string.blank? && email.present?
-      scan = email.scan(/^(.+?)\.(.+?)@.+?$/)
+      scan = email.scan(%r{^(.+?)\.(.+?)@.+?$})
       if scan[0].present?
         if scan[0][0].present?
           firstname = scan[0][0].strip
@@ -900,10 +900,10 @@ try to find correct name
     self.firstname = local_firstname if local_firstname.present?
     self.lastname = local_lastname if local_lastname.present?
 
-    if firstname.present? && firstname.match(/^[A-z]+$/) && (firstname.downcase == firstname || firstname.upcase == firstname)
+    if firstname.present? && firstname.match(%r{^[A-z]+$}) && (firstname.downcase == firstname || firstname.upcase == firstname)
       firstname.capitalize!
     end
-    if lastname.present? && lastname.match(/^[A-z]+$/) && (lastname.downcase == lastname || lastname.upcase == lastname)
+    if lastname.present? && lastname.match(%r{^[A-z]+$}) && (lastname.downcase == lastname || lastname.upcase == lastname)
       lastname.capitalize!
     end
     true
diff --git a/config/initializers/inflections.rb b/config/initializers/inflections.rb
index ab5925cb1..1b3424958 100644
--- a/config/initializers/inflections.rb
+++ b/config/initializers/inflections.rb
@@ -19,7 +19,7 @@ ActiveSupport::Inflector.inflections(:en) do |inflect|
 
   # Rails thinks the singularized version of knowledge_bases is knowledge_basis?!
   # see: KnowledgeBase.table_name.singularize
-  inflect.singular(/(knowledge_base)s$/i, '\1')
+  inflect.singular(%r{(knowledge_base)s$}i, '\1')
   inflect.acronym 'SMIME'
   inflect.acronym 'GitLab'
   inflect.acronym 'GitHub'
diff --git a/config/routes/http_log.rb b/config/routes/http_log.rb
index 0258934e0..2878ff806 100644
--- a/config/routes/http_log.rb
+++ b/config/routes/http_log.rb
@@ -2,7 +2,7 @@ Zammad::Application.routes.draw do
   api_path = Rails.configuration.api_path
 
   match api_path + '/http_logs',            to: 'http_logs#index',   via: :get
-  match api_path + '/http_logs/:facility',  to: 'http_logs#index',   via: :get, constraints: { facility: /.*/ }
+  match api_path + '/http_logs/:facility',  to: 'http_logs#index',   via: :get, constraints: { facility: %r{.*} }
   match api_path + '/http_logs',            to: 'http_logs#create',  via: :post
 
 end
diff --git a/lib/calendar_subscriptions.rb b/lib/calendar_subscriptions.rb
index 06689f10c..6c6a26575 100644
--- a/lib/calendar_subscriptions.rb
+++ b/lib/calendar_subscriptions.rb
@@ -9,7 +9,7 @@ class CalendarSubscriptions
     default_preferences = Setting.where(area: 'Defaults::CalendarSubscriptions')
     default_preferences.each do |calendar_subscription|
 
-      next if calendar_subscription.name !~ /\Adefaults_calendar_subscriptions_(.*)\z/
+      next if calendar_subscription.name !~ %r{\Adefaults_calendar_subscriptions_(.*)\z}
 
       object_name                 = $1 # rubocop:disable Lint/OutOfRangeRegexpRef
       @preferences[ object_name ] = calendar_subscription.state_current[:value]
diff --git a/lib/color_validator.rb b/lib/color_validator.rb
index 000c29f3c..b7add5b5b 100644
--- a/lib/color_validator.rb
+++ b/lib/color_validator.rb
@@ -1,8 +1,8 @@
 class ColorValidator < ActiveModel::EachValidator
   REGEXP = {
-    RGB: /^rgb\((((((((1?[1-9]?\d)|10\d|(2[0-4]\d)|25[0-5]),\s?)){2}|((((1?[1-9]?\d)|10\d|(2[0-4]\d)|25[0-5])\s)){2})((1?[1-9]?\d)|10\d|(2[0-4]\d)|25[0-5]))|((((([1-9]?\d(\.\d+)?)|100|(\.\d+))%,\s?){2}|((([1-9]?\d(\.\d+)?)|100|(\.\d+))%\s){2})(([1-9]?\d(\.\d+)?)|100|(\.\d+))%))\)$/i,
-    HSL: /^hsl\(((((([12]?[1-9]?\d)|[12]0\d|(3[0-6]\d))(\.\d+)?)|(\.\d+))(deg)?|(0|0?\.\d+)turn|(([0-6](\.\d+)?)|(\.\d+))rad)((,\s?(([1-9]?\d(\.\d+)?)|100|(\.\d+))%){2}|(\s(([1-9]?\d(\.\d+)?)|100|(\.\d+))%){2})\)$/i,
-    HEX: /^#([\da-f]{3}){1,2}$/i
+    RGB: %r{^rgb\((((((((1?[1-9]?\d)|10\d|(2[0-4]\d)|25[0-5]),\s?)){2}|((((1?[1-9]?\d)|10\d|(2[0-4]\d)|25[0-5])\s)){2})((1?[1-9]?\d)|10\d|(2[0-4]\d)|25[0-5]))|((((([1-9]?\d(\.\d+)?)|100|(\.\d+))%,\s?){2}|((([1-9]?\d(\.\d+)?)|100|(\.\d+))%\s){2})(([1-9]?\d(\.\d+)?)|100|(\.\d+))%))\)$}i,
+    HSL: %r{^hsl\(((((([12]?[1-9]?\d)|[12]0\d|(3[0-6]\d))(\.\d+)?)|(\.\d+))(deg)?|(0|0?\.\d+)turn|(([0-6](\.\d+)?)|(\.\d+))rad)((,\s?(([1-9]?\d(\.\d+)?)|100|(\.\d+))%){2}|(\s(([1-9]?\d(\.\d+)?)|100|(\.\d+))%){2})\)$}i,
+    HEX: %r{^#([\da-f]{3}){1,2}$}i
   }.freeze
 
   def validate_each(record, attribute, value)
diff --git a/lib/core_ext/active_record/connection_adapters/postgresql/schema_statements.rb b/lib/core_ext/active_record/connection_adapters/postgresql/schema_statements.rb
index ae9bc6ee2..442b7a286 100644
--- a/lib/core_ext/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/lib/core_ext/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -13,7 +13,7 @@ module ActiveRecord
           if column_names.instance_of?(Array)
             index_columns_new = []
             column_names.each do |i|
-              if i =~ /^"(name|login|locale|alias)"$/ || i.end_with?('name"')
+              if i =~ %r{^"(name|login|locale|alias)"$} || i.end_with?('name"')
                 index_columns_new.push "LOWER(#{i})"
               else
                 index_columns_new.push i
diff --git a/lib/core_ext/class.rb b/lib/core_ext/class.rb
index be4a97a5e..afe75550c 100644
--- a/lib/core_ext/class.rb
+++ b/lib/core_ext/class.rb
@@ -1,15 +1,15 @@
 class Class
   def to_app_model_url
     @to_app_model_url ||= begin
-      to_s.gsub(/::/, '_')
-          .gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
-          .gsub(/([a-z\d])([A-Z])/, '\1_\2')
+      to_s.gsub(%r{::}, '_')
+          .gsub(%r{([A-Z]+)([A-Z][a-z])}, '\1_\2')
+          .gsub(%r{([a-z\d])([A-Z])}, '\1_\2')
           .tr('-', '_')
           .downcase
     end
   end
 
   def to_app_model
-    @to_app_model ||= to_s.gsub(/::/, '').to_sym
+    @to_app_model ||= to_s.gsub(%r{::}, '').to_sym
   end
 end
diff --git a/lib/core_ext/string.rb b/lib/core_ext/string.rb
index 4adfa75bd..3c9efa5ab 100644
--- a/lib/core_ext/string.rb
+++ b/lib/core_ext/string.rb
@@ -6,8 +6,8 @@ class String
 
   def strip!
     begin
-      sub!(/\A[[[:space:]]\u{200B}\u{FEFF}]+/, '')
-      sub!(/[[[:space:]]\u{200B}\u{FEFF}]+\Z/, '')
+      sub!(%r{\A[[[:space:]]\u{200B}\u{FEFF}]+}, '')
+      sub!(%r{[[[:space:]]\u{200B}\u{FEFF}]+\Z}, '')
 
     # if incompatible encoding regexp match (UTF-8 regexp with ASCII-8BIT string) (Encoding::CompatibilityError), use default
     rescue Encoding::CompatibilityError
@@ -18,8 +18,8 @@ class String
 
   def strip
     begin
-      new_string = sub(/\A[[[:space:]]\u{200B}\u{FEFF}]+/, '')
-      new_string.sub!(/[[[:space:]]\u{200B}\u{FEFF}]+\Z/, '')
+      new_string = sub(%r{\A[[[:space:]]\u{200B}\u{FEFF}]+}, '')
+      new_string.sub!(%r{[[[:space:]]\u{200B}\u{FEFF}]+\Z}, '')
 
     # if incompatible encoding regexp match (UTF-8 regexp with ASCII-8BIT string) (Encoding::CompatibilityError), use default
     rescue Encoding::CompatibilityError
@@ -46,7 +46,7 @@ class String
 
     lines = self
     lines.split("\n").collect do |line|
-      line.length > options[:line_width] ? line.gsub(/(.{1,#{options[:line_width]}})(\s+|$)/, "\\1\n").strip : line
+      line.length > options[:line_width] ? line.gsub(%r{(.{1,#{options[:line_width]}})(\s+|$)}, "\\1\n").strip : line
     end * "\n"
   end
 
@@ -61,9 +61,9 @@ class String
 
   def to_filename
     camel_cased_word = dup
-    camel_cased_word.gsub(/::/, '/')
-                    .gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
-                    .gsub(/([a-z\d])([A-Z])/, '\1_\2')
+    camel_cased_word.gsub(%r{::}, '/')
+                    .gsub(%r{([A-Z]+)([A-Z][a-z])}, '\1_\2')
+                    .gsub(%r{([a-z\d])([A-Z])}, '\1_\2')
                     .tr('-', '_').downcase
   end
 
@@ -119,7 +119,7 @@ class String
     end
 
     # remove html comments
-    string.gsub!(/<!--.+?-->/m, '')
+    string.gsub!(%r{<!--.+?-->}m, '')
 
     # find <a href=....> and replace it with [x]
     link_list = ''
@@ -128,7 +128,7 @@ class String
       string.gsub!(%r{<a[[:space:]]+(|\S+[[:space:]]+)href=("|')(.+?)("|')([[:space:]]*|[[:space:]]+[^>]*)>(.+?)<[[:space:]]*/a[[:space:]]*>}mxi) do |_placeholder|
         link = $3
         text = $6
-        text.gsub!(/<.+?>/, '')
+        text.gsub!(%r{<.+?>}, '')
 
         link_compare = link.dup
         if link_compare.present?
@@ -147,18 +147,18 @@ class String
 
         if link_compare.present? && text_compare.blank?
           link
-        elsif (link_compare.blank? && text_compare.present?) || (link_compare && link_compare =~ /^mailto/i)
+        elsif (link_compare.blank? && text_compare.present?) || (link_compare && link_compare =~ %r{^mailto}i)
           text
         elsif link_compare.present? && text_compare.present? && (link_compare == text_compare || link_compare == "mailto:#{text}".downcase || link_compare == "http://#{text}".downcase)
           "######LINKEXT:#{link}/TEXT:#{text}######"
-        elsif text !~ /^http/
+        elsif text !~ %r{^http}
           "#{text} (######LINKRAW:#{link}######)"
         else
           "#{link} (######LINKRAW:#{text}######)"
         end
       end
-    elsif string.scan(/<a[[:space:]]/i).count < 5_000
-      string.gsub!(/<a[[:space:]].*?href=("|')(.+?)("|').*?>/ix) do
+    elsif string.scan(%r{<a[[:space:]]}i).count < 5_000
+      string.gsub!(%r{<a[[:space:]].*?href=("|')(.+?)("|').*?>}ix) do
         link = $2
         counter = counter + 1
         link_list += "[#{counter}] #{link}\n"
@@ -170,35 +170,35 @@ class String
     string.gsub!(%r{<style(|[[:space:]].+?)>(.+?)</style>}im, '')
 
     # remove empty lines
-    string.gsub!(/^[[:space:]]*/m, '')
+    string.gsub!(%r{^[[:space:]]*}m, '')
     if strict
       string.gsub!(%r{< [[:space:]]* (/*) [[:space:]]* (b|i|ul|ol|li|u|h1|h2|h3|hr) ([[:space:]]*|[[:space:]]+[^>]*) >}mxi, '######\1\2######')
     end
 
     # pre/code handling 1/2
     string.gsub!(%r{<pre>(.+?)</pre>}m) do |placeholder|
-      placeholder.gsub(/\n/, '###BR###')
+      placeholder.gsub(%r{\n}, '###BR###')
     end
     string.gsub!(%r{<code>(.+?)</code>}m) do |placeholder|
-      placeholder.gsub(/\n/, '###BR###')
+      placeholder.gsub(%r{\n}, '###BR###')
     end
 
     # insert spaces on [A-z]\n[A-z]
-    string.gsub!(/([A-z])[[:space:]]([A-z])/m, '\1 \2')
+    string.gsub!(%r{([A-z])[[:space:]]([A-z])}m, '\1 \2')
 
     # remove all new lines
-    string.gsub!(/(\n\r|\r\r\n|\r\n|\n)/, '')
+    string.gsub!(%r{(\n\r|\r\r\n|\r\n|\n)}, '')
 
     # blockquote handling
     string.gsub!(%r{<blockquote(| [^>]*)>(.+?)</blockquote>}m) do
-      "\n#{$2.html2text(true).gsub(/^(.*)$/, '&gt; \1')}\n"
+      "\n#{$2.html2text(true).gsub(%r{^(.*)$}, '&gt; \1')}\n"
     end
 
     # pre/code handling 2/2
-    string.gsub!(/###BR###/, "\n")
+    string.gsub!(%r{###BR###}, "\n")
 
     # add counting
-    string.gsub!(/<li(| [^>]*)>/i, "\n* ")
+    string.gsub!(%r{<li(| [^>]*)>}i, "\n* ")
 
     # add hr
     string.gsub!(%r{<hr(|/| [^>]*)>}i, "\n___\n")
@@ -214,10 +214,10 @@ class String
     string.gsub!(%r{</td>}i, ' ')
 
     # strip all other tags
-    string.gsub!(/<.+?>/, '')
+    string.gsub!(%r{<.+?>}, '')
 
     # replace multiple spaces with one
-    string.gsub!(/  /, ' ')
+    string.gsub!(%r{  }, ' ')
 
     # add hyperlinks
     if strict
@@ -225,11 +225,11 @@ class String
         pre = $1
         content = $2
         post = $5
-        if content.match?(/^www/i)
+        if content.match?(%r{^www}i)
           content = "http://#{content}"
         end
 
-        if content =~ /^(http|https|ftp|tel)/i
+        if content =~ %r{^(http|https|ftp|tel)}i
           "#{pre}######LINKRAW:#{content}#######{post}"
         else
           "#{pre}#{content}#{post}"
@@ -250,12 +250,12 @@ class String
       string.gsub!('&nbsp;', ' ')
 
       # encode html entities like "&#8211;"
-      string.gsub!(/(&\#(\d+);?)/x) do
+      string.gsub!(%r{(&\#(\d+);?)}x) do
         $2.chr
       end
 
       # encode html entities like "&#3d;"
-      string.gsub!(/(&\#[xX]([0-9a-fA-F]+);?)/x) do
+      string.gsub!(%r{(&\#[xX]([0-9a-fA-F]+);?)}x) do
         chr_orig = $1
         hex      = $2.hex
         if hex
@@ -283,10 +283,10 @@ class String
     string = string.utf8_encode(fallback: :read_as_sanitized_binary)
 
     # remove tailing empty spaces
-    string.gsub!(/[[:blank:]]+$/, '')
+    string.gsub!(%r{[[:blank:]]+$}, '')
 
     # remove double multiple empty lines
-    string.gsub!(/\n\n\n+/, "\n\n")
+    string.gsub!(%r{\n\n\n+}, "\n\n")
 
     # add extracted links
     if link_list != ''
@@ -294,7 +294,7 @@ class String
     end
 
     # remove double multiple empty lines
-    string.gsub!(/\n\n\n+/, "\n\n")
+    string.gsub!(%r{\n\n\n+}, "\n\n")
 
     string.strip
   end
@@ -307,7 +307,7 @@ class String
 
   def text2html
     text = CGI.escapeHTML(self)
-    text.gsub!(/\n/, '<br>')
+    text.gsub!(%r{\n}, '<br>')
     text.chomp
   end
 
@@ -327,8 +327,8 @@ class String
       string = html2text.text2html
       string.signature_identify('text')
       marker_template = '<span class="js-signatureMarker"></span>'
-      string.sub!(/######SIGNATURE_MARKER######/, marker_template)
-      string.gsub!(/######SIGNATURE_MARKER######/, '')
+      string.sub!(%r{######SIGNATURE_MARKER######}, marker_template)
+      string.gsub!(%r{######SIGNATURE_MARKER######}, '')
       return string.chomp
     end
     string.gsub!(%r{(<p>[[:space:]]*</p>([[:space:]]*)){2,}}im, '<p>&nbsp;</p>\2')
@@ -340,7 +340,7 @@ class String
     string.gsub!(%r{<p>[[:space:]]*</p>(<br(|/)>[[:space:]]*)+<p>[[:space:]]*</p>}im, '<p> </p><p> </p>')
     string.gsub!(%r\(<div>[[:space:]]*</div>[[:space:]]*){2,}\im, '<div> </div>')
     string.gsub!(%r{<div>&nbsp;</div>[[:space:]]*(<div>&nbsp;</div>){1,}}im, '<div>&nbsp;</div>')
-    string.gsub!(/(<br>[[:space:]]*){3,}/im, '<br><br>')
+    string.gsub!(%r{(<br>[[:space:]]*){3,}}im, '<br><br>')
     string.gsub!(%r\(<br(|/)>[[:space:]]*){3,}\im, '<br/><br/>')
     string.gsub!(%r{<p>[[:space:]]+</p>}im, '<p>&nbsp;</p>')
     string.gsub!(%r{\A(<br(|/)>[[:space:]]*)*}i, '')
@@ -350,8 +350,8 @@ class String
     string.signature_identify('html')
 
     marker_template = '<span class="js-signatureMarker"></span>'
-    string.sub!(/######SIGNATURE_MARKER######/, marker_template)
-    string.gsub!(/######SIGNATURE_MARKER######/, '')
+    string.sub!(%r{######SIGNATURE_MARKER######}, marker_template)
+    string.gsub!(%r{######SIGNATURE_MARKER######}, '')
     string.chomp
   end
 
@@ -371,7 +371,7 @@ class String
         '<div(|.+?)>[[:space:]]*<br>[[:space:]]*(On|Am|Le|El|Den|Dňa|W dniu|Il|Op|Dne|Dana)[[:space:]].{1,500}<blockquote',
       ]
       map.each do |regexp|
-        string.sub!(/#{regexp}/m) do |placeholder|
+        string.sub!(%r{#{regexp}}m) do |placeholder|
           "#{marker}#{placeholder}"
         end
       end
@@ -385,7 +385,7 @@ class String
     end
 
     # search for signature separator "--\n"
-    string.sub!(/^\s{0,2}--\s{0,2}$/) do |placeholder|
+    string.sub!(%r{^\s{0,2}--\s{0,2}$}) do |placeholder|
       "#{marker}#{placeholder}"
     end
 
@@ -442,7 +442,7 @@ class String
     #map['word-en-de'] = "[^#{marker}].{1,250}\s(wrote|schrieb):"
 
     map.each_value do |regexp|
-      string.sub!(/#{regexp}/) do |placeholder|
+      string.sub!(%r{#{regexp}}) do |placeholder|
         "#{marker}#{placeholder}"
       rescue
         # regexp was not possible because of some string encoding issue, use next
diff --git a/lib/email_helper.rb b/lib/email_helper.rb
index 0d78f11e4..7b548144b 100644
--- a/lib/email_helper.rb
+++ b/lib/email_helper.rb
@@ -60,7 +60,7 @@ returns
   def self.parse_email(email)
     user   = nil
     domain = nil
-    if email =~ /^(.+?)@(.+?)$/
+    if email =~ %r{^(.+?)@(.+?)$}
       user   = $1
       domain = $2
     end
diff --git a/lib/email_helper/probe.rb b/lib/email_helper/probe.rb
index 2119da811..26adeef41 100644
--- a/lib/email_helper/probe.rb
+++ b/lib/email_helper/probe.rb
@@ -71,7 +71,7 @@ returns on fail
       provider_map.each_value do |settings|
         domains.each do |domain_to_check|
 
-          next if !domain_to_check.match?(/#{settings[:domain]}/i)
+          next if !domain_to_check.match?(%r{#{settings[:domain]}}i)
 
           # add folder to config if needed
           if params[:folder].present? && settings[:inbound] && settings[:inbound][:options]
@@ -347,7 +347,7 @@ returns on fail
           }
           white_map.each_key do |key|
 
-            next if !e.message.match?(/#{Regexp.escape(key)}/i)
+            next if !e.message.match?(%r{#{Regexp.escape(key)}}i)
 
             return {
               result:   'ok',
@@ -372,7 +372,7 @@ returns on fail
 
     def self.invalid_field(message_backend)
       invalid_fields.each do |key, fields|
-        return fields if message_backend.match?(/#{Regexp.escape(key)}/i)
+        return fields if message_backend.match?(%r{#{Regexp.escape(key)}}i)
       end
       {}
     end
@@ -397,7 +397,7 @@ returns on fail
 
     def self.translation(message_backend)
       translations.each do |key, message_human|
-        return message_human if message_backend.match?(/#{Regexp.escape(key)}/i)
+        return message_human if message_backend.match?(%r{#{Regexp.escape(key)}}i)
       end
       nil
     end
diff --git a/lib/html_sanitizer.rb b/lib/html_sanitizer.rb
index 53d335cbc..534b354e7 100644
--- a/lib/html_sanitizer.rb
+++ b/lib/html_sanitizer.rb
@@ -62,7 +62,7 @@ satinize html string based on whiltelist
         # prepare src attribute
         if node['src']
           src = cleanup_target(CGI.unescape(node['src']))
-          if src =~ /(javascript|livescript|vbscript):/i || src.downcase.start_with?('http', 'ftp', '//')
+          if src =~ %r{(javascript|livescript|vbscript):}i || src.downcase.start_with?('http', 'ftp', '//')
             node.remove
             Loofah::Scrubber::STOP
           end
@@ -70,7 +70,7 @@ satinize html string based on whiltelist
 
         # clean class / only use allowed classes
         if node['class']
-          classes = node['class'].gsub(/\t|\n|\r/, '').split
+          classes = node['class'].gsub(%r{\t|\n|\r}, '').split
           class_new = ''
           classes.each do |local_class|
             next if classes_whitelist.exclude?(local_class.to_s.strip)
@@ -100,13 +100,13 @@ satinize html string based on whiltelist
           node.delete(key)
           next if value.blank?
 
-          value += 'px' if !value.match?(/%|px|em/i)
+          value += 'px' if !value.match?(%r{%|px|em}i)
           node['style'] += "#{key}:#{value}"
         end
 
         # clean style / only use allowed style properties
         if node['style']
-          pears = node['style'].downcase.gsub(/\t|\n|\r/, '').split(';')
+          pears = node['style'].downcase.gsub(%r{\t|\n|\r}, '').split(';')
           style = ''
           pears.each do |local_pear|
             prop = local_pear.split(':')
@@ -115,7 +115,7 @@ satinize html string based on whiltelist
             key = prop[0].strip
             next if css_properties_whitelist.exclude?(node.name)
             next if css_properties_whitelist[node.name].exclude?(key)
-            next if css_values_blacklist[node.name]&.include?(local_pear.gsub(/[[:space:]]/, '').strip)
+            next if css_values_blacklist[node.name]&.include?(local_pear.gsub(%r{[[:space:]]}, '').strip)
 
             style += "#{local_pear};"
           end
@@ -130,7 +130,7 @@ satinize html string based on whiltelist
           next if !node[attribute_name]
 
           href = cleanup_target(node[attribute_name])
-          next if !href.match?(/(javascript|livescript|vbscript):/i)
+          next if !href.match?(%r{(javascript|livescript|vbscript):}i)
 
           node.delete(attribute_name)
         end
@@ -159,8 +159,8 @@ satinize html string based on whiltelist
         # wrap plain-text URLs in <a> tags
         if node.is_a?(Nokogiri::XML::Text) && node.content.present? && node.content.include?(':') && node.ancestors.map(&:name).exclude?('a')
           urls = URI.extract(node.content, LINKABLE_URL_SCHEMES)
-                    .map { |u| u.sub(/[,.]$/, '') }      # URI::extract captures trailing dots/commas
-                    .reject { |u| u.match?(/^[^:]+:$/) } # URI::extract will match, e.g., 'tel:'
+                    .map { |u| u.sub(%r{[,.]$}, '') }      # URI::extract captures trailing dots/commas
+                    .reject { |u| u.match?(%r{^[^:]+:$}) } # URI::extract will match, e.g., 'tel:'
 
           next if urls.blank?
 
@@ -170,14 +170,14 @@ satinize html string based on whiltelist
         # prepare links
         if node['href']
           href                = cleanup_target(node['href'], keep_spaces: true)
-          href_without_spaces = href.gsub(/[[:space:]]/, '')
+          href_without_spaces = href.gsub(%r{[[:space:]]}, '')
           if external && href_without_spaces.present? && !href_without_spaces.downcase.start_with?('mailto:') && !href_without_spaces.downcase.start_with?('//') && href_without_spaces.downcase !~ %r{^.{1,6}://.+?}
             node['href']        = "http://#{node['href']}"
             href                = node['href']
-            href_without_spaces = href.gsub(/[[:space:]]/, '')
+            href_without_spaces = href.gsub(%r{[[:space:]]}, '')
           end
 
-          next if !CGI.unescape(href_without_spaces).utf8_encode(fallback: :read_as_sanitized_binary).gsub(/[[:space:]]/, '').downcase.start_with?('http', 'ftp', '//')
+          next if !CGI.unescape(href_without_spaces).utf8_encode(fallback: :read_as_sanitized_binary).gsub(%r{[[:space:]]}, '').downcase.start_with?('http', 'ftp', '//')
 
           node.set_attribute('href', href)
           node.set_attribute('rel', 'nofollow noreferrer noopener')
@@ -219,15 +219,15 @@ cleanup html string:
 
   def self.cleanup(string, timeout: true)
     Timeout.timeout(timeout ? PROCESSING_TIMEOUT : nil) do
-      string.gsub!(/<[A-z]:[A-z]>/, '')
+      string.gsub!(%r{<[A-z]:[A-z]>}, '')
       string.gsub!(%r{</[A-z]:[A-z]>}, '')
       string.delete!("\t")
 
       # remove all new lines
-      string.gsub!(/(\n\r|\r\r\n|\r\n|\n)/, "\n")
+      string.gsub!(%r{(\n\r|\r\r\n|\r\n|\n)}, "\n")
 
       # remove double multiple empty lines
-      string.gsub!(/\n\n\n+/, "\n\n")
+      string.gsub!(%r{\n\n\n+}, "\n\n")
 
       string = cleanup_structure(string, 'pre')
       string = cleanup_structure(string)
@@ -302,7 +302,7 @@ cleanup html string:
           content = node.content
           if content
             if content != ' ' && content != "\n"
-              content.gsub!(/[[:space:]]+/, ' ')
+              content.gsub!(%r{[[:space:]]+}, ' ')
             end
             if node.previous
               if node.previous.name == 'div' || node.previous.name == 'p'
@@ -329,11 +329,11 @@ cleanup html string:
     end
     url = urls.shift
 
-    if content =~ /^(.*)#{Regexp.quote(url)}(.*)$/mx
+    if content =~ %r{^(.*)#{Regexp.quote(url)}(.*)$}mx
       pre = $1
       post = $2
 
-      if url.match?(/^www/i)
+      if url.match?(%r{^www}i)
         url = "http://#{url}"
       end
 
@@ -367,11 +367,11 @@ cleanup html string:
 
   def self.cleanup_target(string, **options)
     cleaned_string = string.utf8_encode(fallback: :read_as_sanitized_binary)
-    cleaned_string = cleaned_string.gsub(/[[:space:]]/, '') if !options[:keep_spaces]
+    cleaned_string = cleaned_string.gsub(%r{[[:space:]]}, '') if !options[:keep_spaces]
     cleaned_string = cleaned_string.strip
                                    .delete("\t\n\r\u0000")
                                    .gsub(%r{/\*.*?\*/}, '')
-                                   .gsub(/<!--.*?-->/, '')
+                                   .gsub(%r{<!--.*?-->}, '')
 
     sanitize_attachment_disposition(cleaned_string)
   end
@@ -392,8 +392,8 @@ cleanup html string:
   end
 
   def self.url_same?(url_new, url_old)
-    url_new = CGI.unescape(url_new.to_s).utf8_encode(fallback: :read_as_sanitized_binary).downcase.delete_suffix('/').gsub(/[[:space:]]|\t|\n|\r/, '').strip
-    url_old = CGI.unescape(url_old.to_s).utf8_encode(fallback: :read_as_sanitized_binary).downcase.delete_suffix('/').gsub(/[[:space:]]|\t|\n|\r/, '').strip
+    url_new = CGI.unescape(url_new.to_s).utf8_encode(fallback: :read_as_sanitized_binary).downcase.delete_suffix('/').gsub(%r{[[:space:]]|\t|\n|\r}, '').strip
+    url_old = CGI.unescape(url_old.to_s).utf8_encode(fallback: :read_as_sanitized_binary).downcase.delete_suffix('/').gsub(%r{[[:space:]]|\t|\n|\r}, '').strip
     url_new = html_decode(url_new).sub('/?', '?')
     url_old = html_decode(url_old).sub('/?', '?')
     return true if url_new == url_old
@@ -460,7 +460,7 @@ satinize style of img tags
         if node['src']
           style = 'max-width:100%;'
           if node['style']
-            pears = node['style'].downcase.gsub(/\t|\n|\r/, '').split(';')
+            pears = node['style'].downcase.gsub(%r{\t|\n|\r}, '').split(';')
             pears.each do |local_pear|
               prop = local_pear.split(':')
               next if !prop[0]
diff --git a/lib/idoit.rb b/lib/idoit.rb
index a40a1d112..f7fdaf9b4 100644
--- a/lib/idoit.rb
+++ b/lib/idoit.rb
@@ -124,7 +124,7 @@ or with filter:
       },
     )
 
-    raise "Can't fetch objects from #{url}: Unable to parse response from server. Invalid JSON response." if !result.success? && result.error =~ /JSON::ParserError:.+?\s+unexpected\s+token\s+at\s+'<!DOCTYPE\s+html/i
+    raise "Can't fetch objects from #{url}: Unable to parse response from server. Invalid JSON response." if !result.success? && result.error =~ %r{JSON::ParserError:.+?\s+unexpected\s+token\s+at\s+'<!DOCTYPE\s+html}i
     raise "Can't fetch objects from #{url}: #{result.error}" if !result.success?
 
     # add link to idoit
diff --git a/lib/import/base_factory.rb b/lib/import/base_factory.rb
index c7afc4a8d..945211c59 100644
--- a/lib/import/base_factory.rb
+++ b/lib/import/base_factory.rb
@@ -39,7 +39,7 @@ module Import
     end
 
     def module_name
-      name.to_s.sub(/Import::/, '').sub(/Factory/, '')
+      name.to_s.sub(%r{Import::}, '').sub(%r{Factory}, '')
     end
   end
 end
diff --git a/lib/import/helper/attributes_examples.rb b/lib/import/helper/attributes_examples.rb
index d362d1709..1909b5ba0 100644
--- a/lib/import/helper/attributes_examples.rb
+++ b/lib/import/helper/attributes_examples.rb
@@ -60,7 +60,7 @@ module Import
           next if value.nil?
 
           example = value.to_utf8(fallback: :read_as_sanitized_binary)
-          example.gsub!(/^(.{20,}?).*$/m, '\1...')
+          example.gsub!(%r{^(.{20,}?).*$}m, '\1...')
 
           @examples[attribute] = "#{attribute} (e. g. #{example})"
         end
diff --git a/lib/import/otrs/article.rb b/lib/import/otrs/article.rb
index 82e0c74cf..6d1215295 100644
--- a/lib/import/otrs/article.rb
+++ b/lib/import/otrs/article.rb
@@ -92,7 +92,7 @@ module Import
         mapped.delete(:content_type) if mapped[:content_type].blank?
         return mapped if !mapped[:content_type]
 
-        mapped[:content_type].sub!(/[;,]\s?.+?$/, '')
+        mapped[:content_type].sub!(%r{[;,]\s?.+?$}, '')
         mapped
       end
 
diff --git a/lib/import/otrs/article_customer.rb b/lib/import/otrs/article_customer.rb
index f0bc15d25..4b46d60cf 100644
--- a/lib/import/otrs/article_customer.rb
+++ b/lib/import/otrs/article_customer.rb
@@ -33,7 +33,7 @@ module Import
         def extract_email(from)
           Mail::Address.new(from).address
         rescue
-          return from if from !~ /<\s*([^>]+)/
+          return from if from !~ %r{<\s*([^>]+)}
 
           $1.strip
         end
diff --git a/lib/import/otrs/dynamic_field.rb b/lib/import/otrs/dynamic_field.rb
index c91b850a9..cb747f04d 100644
--- a/lib/import/otrs/dynamic_field.rb
+++ b/lib/import/otrs/dynamic_field.rb
@@ -14,7 +14,7 @@ module Import
       end
 
       def self.convert_name(dynamic_field_name)
-        dynamic_field_name.underscore.sub(/_id(s)?\z/, '_no\1')
+        dynamic_field_name.underscore.sub(%r{_id(s)?\z}, '_no\1')
       end
 
       private
diff --git a/lib/import/otrs/history/move.rb b/lib/import/otrs/history/move.rb
index 4c07ac959..4fa5d34ad 100644
--- a/lib/import/otrs/history/move.rb
+++ b/lib/import/otrs/history/move.rb
@@ -7,7 +7,7 @@ module Import
           # "%%Queue1%%5%%Postmaster%%1"
           from = nil
           to   = nil
-          if data =~ /%%(.+?)%%(.+?)%%(.+?)%%(.+?)$/
+          if data =~ %r{%%(.+?)%%(.+?)%%(.+?)%%(.+?)$}
             from    = $1
             from_id = $2
             to      = $3
diff --git a/lib/import/otrs/history/priority_update.rb b/lib/import/otrs/history/priority_update.rb
index bad17f2e0..e0a024fbd 100644
--- a/lib/import/otrs/history/priority_update.rb
+++ b/lib/import/otrs/history/priority_update.rb
@@ -7,7 +7,7 @@ module Import
           # "%%3 normal%%3%%5 very high%%5"
           from = nil
           to   = nil
-          if data =~ /%%(.+?)%%(.+?)%%(.+?)%%(.+?)$/
+          if data =~ %r{%%(.+?)%%(.+?)%%(.+?)%%(.+?)$}
             from    = $1
             from_id = $2
             to      = $3
diff --git a/lib/import/otrs/history/state_update.rb b/lib/import/otrs/history/state_update.rb
index 0e199c517..94372de88 100644
--- a/lib/import/otrs/history/state_update.rb
+++ b/lib/import/otrs/history/state_update.rb
@@ -7,7 +7,7 @@ module Import
           # "%%new%%open%%"
           from = nil
           to   = nil
-          if data =~ /%%(.+?)%%(.+?)%%/
+          if data =~ %r{%%(.+?)%%(.+?)%%}
             from    = $1
             to      = $2
             state_from = ::Ticket::State.lookup(name: from)
diff --git a/lib/import/otrs/user.rb b/lib/import/otrs/user.rb
index b76c84e9d..aa38f546f 100644
--- a/lib/import/otrs/user.rb
+++ b/lib/import/otrs/user.rb
@@ -161,7 +161,7 @@ module Import
           result.push 'Admin'
         end
 
-        return result if !group['Name'].match?(/^(stats|report)/)
+        return result if !group['Name'].match?(%r{^(stats|report)})
         return result if !( permissions.include?('ro') || permissions.include?('rw') )
 
         result.push 'Report'
diff --git a/lib/ldap.rb b/lib/ldap.rb
index f11c4bd7d..c04d2e6e4 100644
--- a/lib/ldap.rb
+++ b/lib/ldap.rb
@@ -189,7 +189,7 @@ class Ldap
   end
 
   def parse_host
-    return if @host !~ /\A([^:]+):(.+?)\z/
+    return if @host !~ %r{\A([^:]+):(.+?)\z}
 
     @host = $1
     @port = $2.to_i
diff --git a/lib/ldap/guid.rb b/lib/ldap/guid.rb
index f9371ab22..7a44cba0e 100644
--- a/lib/ldap/guid.rb
+++ b/lib/ldap/guid.rb
@@ -16,7 +16,7 @@ class Ldap
     #
     # @return [Boolean]
     def self.valid?(string)
-      string.match?(/\w{8}-\w{4}-\w{4}-\w{4}-\w+/)
+      string.match?(%r{\w{8}-\w{4}-\w{4}-\w{4}-\w+})
     end
 
     # Convers a given GUID string into the HEX equivalent.
@@ -88,7 +88,7 @@ class Ldap
       string.delete!('-')
 
       # split every two chars
-      parts = string.scan(/.{1,2}/)
+      parts = string.scan(%r{.{1,2}})
 
       # re-order according to oracle format index and join
       oracle_format_indices = [3, 2, 1, 0, 5, 4, 7, 6, 8, 9, 10, 11, 12, 13, 14, 15]
diff --git a/lib/mixin/required_sub_paths.rb b/lib/mixin/required_sub_paths.rb
index b59445b47..ed2852c72 100644
--- a/lib/mixin/required_sub_paths.rb
+++ b/lib/mixin/required_sub_paths.rb
@@ -30,7 +30,7 @@ module Mixin
 
         if File.directory?(sub_path)
           sub_paths.push(sub_path)
-        elsif sub_path =~ /\A(.*)\.rb\z/
+        elsif sub_path =~ %r{\A(.*)\.rb\z}
           require_path = $1
           require_dependency(require_path)
         end
diff --git a/lib/models.rb b/lib/models.rb
index 303e6e8ed..32b9c699d 100644
--- a/lib/models.rb
+++ b/lib/models.rb
@@ -30,7 +30,7 @@ returns
       dir    = Rails.root.join('app/models').to_s
       tables = ActiveRecord::Base.connection.tables
       Dir.glob("#{dir}/**/*.rb") do |entry|
-        next if entry.match?(/application_model/i)
+        next if entry.match?(%r{application_model}i)
         next if entry.match?(%r{channel/}i)
         next if entry.match?(%r{observer/}i)
         next if entry.match?(%r{store/provider/}i)
diff --git a/lib/notification_factory/mailer.rb b/lib/notification_factory/mailer.rb
index d927c2a43..1711e17c7 100644
--- a/lib/notification_factory/mailer.rb
+++ b/lib/notification_factory/mailer.rb
@@ -244,8 +244,8 @@ retunes
     result.each do |item|
       next if item['type'] != 'notification'
       next if item['object'] != 'Ticket'
-      next if !item['value_to'].match?(/#{recipient.email}/i)
-      next if !item['value_to'].match?(/#{type}/i)
+      next if !item['value_to'].match?(%r{#{recipient.email}}i)
+      next if !item['value_to'].match?(%r{#{type}}i)
 
       count += 1
     end
diff --git a/lib/notification_factory/renderer.rb b/lib/notification_factory/renderer.rb
index 6c7086fcc..9f507ed7f 100644
--- a/lib/notification_factory/renderer.rb
+++ b/lib/notification_factory/renderer.rb
@@ -106,7 +106,7 @@ examples how to use
       end
 
       arguments = nil
-      if /\A(?<method_id>[^(]+)\((?<parameter>[^)]+)\)\z/ =~ method
+      if %r{\A(?<method_id>[^(]+)\((?<parameter>[^)]+)\)\z} =~ method
 
         if parameter != parameter.to_i.to_s
           value = "\#{#{object_name}.#{object_methods_s} / invalid parameter: #{parameter}}"
@@ -185,7 +185,7 @@ examples how to use
   end
 
   def data_key_valid?(key)
-    return false if key =~ /`|\.(|\s*)(save|destroy|delete|remove|drop|update|create|new|all|where|find|raise|dump|rollback|freeze)/i && key !~ /(update|create)d_(at|by)/i
+    return false if key =~ %r{`|\.(|\s*)(save|destroy|delete|remove|drop|update|create|new|all|where|find|raise|dump|rollback|freeze)}i && key !~ %r{(update|create)d_(at|by)}i
 
     true
   end
diff --git a/lib/notification_factory/template.rb b/lib/notification_factory/template.rb
index 945eba14d..22e2e90be 100644
--- a/lib/notification_factory/template.rb
+++ b/lib/notification_factory/template.rb
@@ -17,17 +17,17 @@ examples how to use
   end
 
   def to_s
-    @template.gsub(/\#{\s*(.*?)\s*}/m) do
+    @template.gsub(%r{\#{\s*(.*?)\s*}}m) do
       # some browsers start adding HTML tags
       # fixes https://github.com/zammad/zammad/issues/385
-      input_template = $1.gsub(/\A<.+?>\s*|\s*<.+?>\z/, '')
+      input_template = $1.gsub(%r{\A<.+?>\s*|\s*<.+?>\z}, '')
 
       case input_template
-      when /\At\('(.+?)'\)\z/m
+      when %r{\At\('(.+?)'\)\z}m
         %(<%= t "#{sanitize_text($1)}", #{@escape} %>)
-      when /\At\((.+?)\)\z/m
+      when %r{\At\((.+?)\)\z}m
         %(<%= t d"#{sanitize_object_name($1)}", #{@escape} %>)
-      when /\Aconfig\.(.+?)\z/m
+      when %r{\Aconfig\.(.+?)\z}m
         %(<%= c "#{sanitize_object_name($1)}", #{@escape} %>)
       else
         %(<%= d "#{sanitize_object_name(input_template)}", #{@escape} %>)
@@ -37,7 +37,7 @@ examples how to use
 
   def sanitize_text(string)
     string&.tr("\t\r\n", '')
-          &.gsub(/(?<!\\)(?=")/, '\\')
+          &.gsub(%r{(?<!\\)(?=")}, '\\')
   end
 
   def sanitize_object_name(string)
diff --git a/lib/password_hash.rb b/lib/password_hash.rb
index dbdd972f4..37a9ee9b6 100644
--- a/lib/password_hash.rb
+++ b/lib/password_hash.rb
@@ -44,7 +44,7 @@ module PasswordHash
 
   def hashed_argon2i?(pw_hash, password)
     # taken from: https://github.com/technion/ruby-argon2/blob/7e1f4a2634316e370ab84150e4f5fd91d9263713/lib/argon2.rb#L33
-    return false if !pw_hash.match?(/^\$argon2i\$.{,112}/)
+    return false if !pw_hash.match?(%r{^\$argon2i\$.{,112}})
 
     # Argon2::Password.verify_password verifies argon2i hashes, too
     verified?(pw_hash, password)
diff --git a/lib/password_policy/digit.rb b/lib/password_policy/digit.rb
index 4ceebd5f3..de5c351be 100644
--- a/lib/password_policy/digit.rb
+++ b/lib/password_policy/digit.rb
@@ -1,7 +1,7 @@
 class PasswordPolicy
   class Digit < PasswordPolicy::Backend
 
-    NEED_DIGIT_REGEXP = /\d/.freeze
+    NEED_DIGIT_REGEXP = %r{\d}.freeze
 
     def valid?
       @password.match? NEED_DIGIT_REGEXP
diff --git a/lib/password_policy/special_character.rb b/lib/password_policy/special_character.rb
index d1a065412..a159f1636 100644
--- a/lib/password_policy/special_character.rb
+++ b/lib/password_policy/special_character.rb
@@ -1,7 +1,7 @@
 class PasswordPolicy
   class SpecialCharacter < PasswordPolicy::Backend
 
-    NEED_SPECIAL_CHARACTER_REGEXP = /\W/.freeze
+    NEED_SPECIAL_CHARACTER_REGEXP = %r{\W}.freeze
 
     def valid?
       @password.match? NEED_SPECIAL_CHARACTER_REGEXP
diff --git a/lib/password_policy/upper_and_lower_case_characters.rb b/lib/password_policy/upper_and_lower_case_characters.rb
index 95268b49f..6abb89798 100644
--- a/lib/password_policy/upper_and_lower_case_characters.rb
+++ b/lib/password_policy/upper_and_lower_case_characters.rb
@@ -1,7 +1,7 @@
 class PasswordPolicy
   class UpperAndLowerCaseCharacters < PasswordPolicy::Backend
 
-    UPPER_LOWER_REGEXPS = [/\p{Upper}.*\p{Upper}/, /\p{Lower}.*\p{Lower}/].freeze
+    UPPER_LOWER_REGEXPS = [%r{\p{Upper}.*\p{Upper}}, %r{\p{Lower}.*\p{Lower}}].freeze
 
     def valid?
       UPPER_LOWER_REGEXPS.all? { |regexp| @password.match?(regexp) }
diff --git a/lib/report/ticket_generic_time.rb b/lib/report/ticket_generic_time.rb
index a12fb9e12..4c2e85af6 100644
--- a/lib/report/ticket_generic_time.rb
+++ b/lib/report/ticket_generic_time.rb
@@ -88,7 +88,7 @@ returns
           replace = '\d\d:\d\d:\d\dZ$'
         end
 
-        next if key_as_string.iso8601.sub(/#{replace}/, '') != params[:range_start].iso8601.sub(/#{replace}/, '')
+        next if key_as_string.iso8601.sub(%r{#{replace}}, '') != params[:range_start].iso8601.sub(%r{#{replace}}, '')
         next if match
 
         match = true
diff --git a/lib/search_index_backend.rb b/lib/search_index_backend.rb
index f13b2fb3f..9103492f3 100644
--- a/lib/search_index_backend.rb
+++ b/lib/search_index_backend.rb
@@ -342,7 +342,7 @@ remove whole data from index
       next if order_by&.at(index).blank?
 
       # for sorting values use .keyword values (no analyzer is used - plain values)
-      if value !~ /\./ && value !~ /_(time|date|till|id|ids|at)$/
+      if value !~ %r{\.} && value !~ %r{_(time|date|till|id|ids|at)$}
         value += '.keyword'
       end
       result.push(
@@ -511,7 +511,7 @@ example for aggregations within one year
 
           case data['pre_condition']
           when 'not_set'
-            data['value'] = if key_tmp.match?(/^(created_by|updated_by|owner|customer|user)_id/)
+            data['value'] = if key_tmp.match?(%r{^(created_by|updated_by|owner|customer|user)_id})
                               1
                             end
           when 'current_user.id'
@@ -534,12 +534,12 @@ example for aggregations within one year
 
           if data['value'].is_a?(Array)
             data['value'].each do |value|
-              next if !value.is_a?(String) || value !~ /[A-z]/
+              next if !value.is_a?(String) || value !~ %r{[A-z]}
 
               key_tmp += '.keyword'
               break
             end
-          elsif data['value'].is_a?(String) && /[A-z]/.match?(data['value'])
+          elsif data['value'].is_a?(String) && %r{[A-z]}.match?(data['value'])
             key_tmp += '.keyword'
           end
         end
@@ -549,14 +549,14 @@ example for aggregations within one year
 
           if data['value'].is_a?(Array)
             data['value'].each_with_index do |value, index|
-              next if !value.is_a?(String) || value !~ /[A-z]/
+              next if !value.is_a?(String) || value !~ %r{[A-z]}
 
               data['value'][index] = "*#{value}*"
               key_tmp += '.keyword'
               wildcard_or_term = 'wildcards'
               break
             end
-          elsif data['value'].is_a?(String) && /[A-z]/.match?(data['value'])
+          elsif data['value'].is_a?(String) && %r{[A-z]}.match?(data['value'])
             data['value'] = "*#{data['value']}*"
             key_tmp += '.keyword'
             wildcard_or_term = 'wildcard'
diff --git a/lib/sequencer/unit/import/common/object_attribute/sanitized_name.rb b/lib/sequencer/unit/import/common/object_attribute/sanitized_name.rb
index 010746dc5..ab7502a75 100644
--- a/lib/sequencer/unit/import/common/object_attribute/sanitized_name.rb
+++ b/lib/sequencer/unit/import/common/object_attribute/sanitized_name.rb
@@ -18,7 +18,7 @@ class Sequencer
               # model_name
               # model_name_
               # model_name
-              without_double_underscores.gsub(/_id(s?)$/, '_no\1')
+              without_double_underscores.gsub(%r{_id(s?)$}, '_no\1')
             end
 
             def without_double_underscores
@@ -29,7 +29,7 @@ class Sequencer
               # model_name
               # model_name_
               # model_name
-              only_supported_chars.gsub(/_{2,}/, '_')
+              only_supported_chars.gsub(%r{_{2,}}, '_')
             end
 
             def only_supported_chars
@@ -40,7 +40,7 @@ class Sequencer
               # model__name
               # model_name_
               # model_name
-              downcased.split('').map { |char| char.match?(/[a-z0-9_]/) ? char : '_' }.join
+              downcased.split('').map { |char| char.match?(%r{[a-z0-9_]}) ? char : '_' }.join
             end
 
             def downcased
diff --git a/lib/sequencer/unit/import/common/user/email/check_validity.rb b/lib/sequencer/unit/import/common/user/email/check_validity.rb
index 6331eebb3..b876ac12d 100644
--- a/lib/sequencer/unit/import/common/user/email/check_validity.rb
+++ b/lib/sequencer/unit/import/common/user/email/check_validity.rb
@@ -30,13 +30,13 @@ class Sequencer
 
               def extract_email(source)
                 # Support format like "Bob Smith (bob@example.com)"
-                if source =~ /\((.+@.+)\)/
+                if source =~ %r{\((.+@.+)\)}
                   source = $1
                 end
 
                 Mail::Address.new(source).address
               rescue
-                return source if source !~ /<\s*([^>]+)/
+                return source if source !~ %r{<\s*([^>]+)}
 
                 $1.strip
               end
diff --git a/lib/sequencer/unit/import/zendesk/sub_sequence/base.rb b/lib/sequencer/unit/import/zendesk/sub_sequence/base.rb
index ac25648a9..48fb74a6a 100644
--- a/lib/sequencer/unit/import/zendesk/sub_sequence/base.rb
+++ b/lib/sequencer/unit/import/zendesk/sub_sequence/base.rb
@@ -65,7 +65,7 @@ class Sequencer
               return true if e.message.include?('execution expired')
 
               status = e.response.status.to_s
-              status.match?(/^(4|5)\d\d$/)
+              status.match?(%r{^(4|5)\d\d$})
             end
 
             def resource_collection
diff --git a/lib/service/geo_calendar/zammad.rb b/lib/service/geo_calendar/zammad.rb
index 4b9204be3..b4187f564 100644
--- a/lib/service/geo_calendar/zammad.rb
+++ b/lib/service/geo_calendar/zammad.rb
@@ -27,7 +27,7 @@ class Service::GeoCalendar::Zammad
           total_timeout: 12,
         },
       )
-      if !response.success? && response.code.to_s !~ /^40.$/
+      if !response.success? && response.code.to_s !~ %r{^40.$}
         raise "#{response.code}/#{response.body}"
       end
 
diff --git a/lib/service/geo_ip/zammad.rb b/lib/service/geo_ip/zammad.rb
index b2a5025d1..095ce3f57 100644
--- a/lib/service/geo_ip/zammad.rb
+++ b/lib/service/geo_ip/zammad.rb
@@ -25,7 +25,7 @@ class Service::GeoIp::Zammad
           total_timeout: 4,
         },
       )
-      if !response.success? && response.code.to_s !~ /^40.$/
+      if !response.success? && response.code.to_s !~ %r{^40.$}
         raise "#{response.code}/#{response.body}"
       end
 
diff --git a/lib/service/image/zammad.rb b/lib/service/image/zammad.rb
index 335eed867..29379b6e2 100644
--- a/lib/service/image/zammad.rb
+++ b/lib/service/image/zammad.rb
@@ -12,7 +12,7 @@ class Service::Image::Zammad
 
     email.downcase!
 
-    return if email.match?(/@example.com$/)
+    return if email.match?(%r{@example.com$})
 
     # fetch image
     response = UserAgent.post(
@@ -42,7 +42,7 @@ class Service::Image::Zammad
     raise Exceptions::UnprocessableEntity, 'no domain given' if domain.blank?
 
     # strip, just use domain name
-    domain = domain.sub(/^.+?@(.+?)$/, '\1')
+    domain = domain.sub(%r{^.+?@(.+?)$}, '\1')
 
     domain.downcase!
     return if domain == 'example.com'
diff --git a/lib/signature_detection.rb b/lib/signature_detection.rb
index 1421af25c..17669ff21 100644
--- a/lib/signature_detection.rb
+++ b/lib/signature_detection.rb
@@ -42,7 +42,7 @@ returns
 
       # Take up to 10 lines from this "gap" (i.e., the common substring)
       match_content = diff_lines[sig_range.first..sig_range.last]
-                        .map { |l| l.sub(/^./, '') }
+                        .map { |l| l.sub(%r{^.}, '') }
                         .first(10).join("\n")
 
       # Add this substring to the signature_candidates hash and increment its match score
diff --git a/lib/sql_helper.rb b/lib/sql_helper.rb
index aac91e318..0f3ff605c 100644
--- a/lib/sql_helper.rb
+++ b/lib/sql_helper.rb
@@ -9,7 +9,7 @@ class SqlHelper
   def get_param_key(key, params)
     sort_by = []
     if params[key].present? && params[key].is_a?(String)
-      params[key] = params[key].split(/\s*,\s*/)
+      params[key] = params[key].split(%r{\s*,\s*})
     elsif params[key].blank?
       params[key] = []
     end
@@ -79,7 +79,7 @@ order_by = [
 
     # check order
     params[:order_by].each do |value|
-      raise "Found invalid order by value #{value}. Please use 'asc' or 'desc'." if !value.match?(/\A(asc|desc)\z/i)
+      raise "Found invalid order by value #{value}. Please use 'asc' or 'desc'." if !value.match?(%r{\A(asc|desc)\z}i)
 
       order_by.push(value.downcase)
     end
diff --git a/lib/static_assets.rb b/lib/static_assets.rb
index 1b27f339a..1b3d0b278 100644
--- a/lib/static_assets.rb
+++ b/lib/static_assets.rb
@@ -16,7 +16,7 @@ returns
 
   def self.data_url_attributes(data_url)
     data = {}
-    if data_url =~ /^data:(.+?);base64,(.+?)$/
+    if data_url =~ %r{^data:(.+?);base64,(.+?)$}
       data[:mime_type] = $1
       data[:content]   = Base64.decode64($2)
       if data[:mime_type] =~ %r{/(.+?)$}
@@ -146,13 +146,13 @@ generate filename based on Store model
     hash = Digest::MD5.hexdigest(file.content)
     extention = ''
     case file.preferences['Content-Type']
-    when /jpg|jpeg/i
+    when %r{jpg|jpeg}i
       extention = '.jpg'
-    when /png/i
+    when %r{png}i
       extention = '.png'
-    when /gif/i
+    when %r{gif}i
       extention = '.gif'
-    when /svg/i
+    when %r{svg}i
       extention = '.svg'
     end
     "#{hash}#{extention}"
diff --git a/lib/stats/ticket_channel_distribution.rb b/lib/stats/ticket_channel_distribution.rb
index cad03db9c..31fcbc38b 100644
--- a/lib/stats/ticket_channel_distribution.rb
+++ b/lib/stats/ticket_channel_distribution.rb
@@ -86,7 +86,7 @@ class Stats::TicketChannelDistribution
       }
       type_ids = []
       Ticket::Article::Type.all.each do |type|
-        next if !type.name.match?(/^#{channel[:sender]}/i)
+        next if !type.name.match?(%r{^#{channel[:sender]}}i)
 
         type_ids.push type.id
       end
diff --git a/lib/twitter_sync.rb b/lib/twitter_sync.rb
index 4557dcd81..ba313a0a0 100644
--- a/lib/twitter_sync.rb
+++ b/lib/twitter_sync.rb
@@ -203,9 +203,9 @@ class TwitterSync
           next if local_url['url'].blank?
 
           if local_url['expanded_url'].present?
-            text.gsub!(/#{Regexp.quote(local_url['url'])}/, local_url['expanded_url'])
+            text.gsub!(%r{#{Regexp.quote(local_url['url'])}}, local_url['expanded_url'])
           elsif local_url['display_url']
-            text.gsub!(/#{Regexp.quote(local_url['url'])}/, local_url['display_url'])
+            text.gsub!(%r{#{Regexp.quote(local_url['url'])}}, local_url['display_url'])
           end
         end
       end
@@ -266,9 +266,9 @@ class TwitterSync
 
           if local_media['url'].present?
             if local_media['expanded_url'].present?
-              text.gsub!(/#{Regexp.quote(local_media['url'])}/, local_media['expanded_url'])
+              text.gsub!(%r{#{Regexp.quote(local_media['url'])}}, local_media['expanded_url'])
             elsif local_media['display_url']
-              text.gsub!(/#{Regexp.quote(local_media['url'])}/, local_media['display_url'])
+              text.gsub!(%r{#{Regexp.quote(local_media['url'])}}, local_media['display_url'])
             end
           end
         end
@@ -277,9 +277,9 @@ class TwitterSync
 
           if local_media['url'].present?
             if local_media['expanded_url'].present?
-              text.gsub!(/#{Regexp.quote(local_media['url'])}/, local_media['expanded_url'])
+              text.gsub!(%r{#{Regexp.quote(local_media['url'])}}, local_media['expanded_url'])
             elsif local_media['display_url']
-              text.gsub!(/#{Regexp.quote(local_media['url'])}/, local_media['display_url'])
+              text.gsub!(%r{#{Regexp.quote(local_media['url'])}}, local_media['display_url'])
             end
           end
 
@@ -723,7 +723,7 @@ process webhook messages from twitter
           channel.options[:sync][:search].each do |local_search|
             next if local_search[:term].blank?
             next if local_search[:group_id].blank?
-            next if !item['text'].match?(/#{Regexp.quote(local_search[:term])}/i)
+            next if !item['text'].match?(%r{#{Regexp.quote(local_search[:term])}}i)
 
             group_id = local_search[:group_id]
             break
diff --git a/lib/user_agent.rb b/lib/user_agent.rb
index 7d2af693b..58881a7e4 100644
--- a/lib/user_agent.rb
+++ b/lib/user_agent.rb
@@ -287,9 +287,9 @@ returns
 
     uri = URI.parse(url)
     case uri.scheme.downcase
-    when /ftp/
+    when %r{ftp}
       ftp(uri, options)
-    when /http|https/
+    when %r{http|https}
       get(url, {}, options)
     end
 
@@ -302,7 +302,7 @@ returns
     proxy_no = proxy_no.split(',').map(&:strip) || []
     proxy_no.push('localhost', '127.0.0.1', '::1')
     if proxy.present? && proxy_no.exclude?(uri.host.downcase)
-      if proxy =~ /^(.+?):(.+?)$/
+      if proxy =~ %r{^(.+?):(.+?)$}
         proxy_host = $1
         proxy_port = $2
       end
@@ -328,7 +328,7 @@ returns
     http.open_timeout = options[:open_timeout] || 4
     http.read_timeout = options[:read_timeout] || 10
 
-    if uri.scheme.match?(/https/i)
+    if uri.scheme.match?(%r{https}i)
       http.use_ssl = true
 
       if !options.fetch(:verify_ssl, false)
diff --git a/spec/lib/external_credential/google_spec.rb b/spec/lib/external_credential/google_spec.rb
index aa593f679..e26cfc1e1 100644
--- a/spec/lib/external_credential/google_spec.rb
+++ b/spec/lib/external_credential/google_spec.rb
@@ -299,7 +299,7 @@ RSpec.describe ExternalCredential::Google do
             error_description: 'The OAuth client was not found.'
           }
         end
-        let(:exception_message) { /The OAuth client was not found/ }
+        let(:exception_message) { %r{The OAuth client was not found} }
 
         include_examples 'failed attempt'
       end
@@ -307,7 +307,7 @@ RSpec.describe ExternalCredential::Google do
       context '500 Internal Server Error' do
         let(:response_status) { 500 }
         let(:response_payload) { nil }
-        let(:exception_message) { /code: 500/ }
+        let(:exception_message) { %r{code: 500} }
 
         include_examples 'failed attempt'
       end
diff --git a/spec/lib/external_credential/microsoft365_spec.rb b/spec/lib/external_credential/microsoft365_spec.rb
index 7e429e43f..afd49f1bc 100644
--- a/spec/lib/external_credential/microsoft365_spec.rb
+++ b/spec/lib/external_credential/microsoft365_spec.rb
@@ -260,7 +260,7 @@ RSpec.describe ExternalCredential::Microsoft365 do
             error_description: 'The OAuth client was not found.'
           }
         end
-        let(:exception_message) { /The OAuth client was not found/ }
+        let(:exception_message) { %r{The OAuth client was not found} }
 
         include_examples 'failed attempt'
       end
@@ -268,7 +268,7 @@ RSpec.describe ExternalCredential::Microsoft365 do
       context '500 Internal Server Error' do
         let(:response_status) { 500 }
         let(:response_payload) { nil }
-        let(:exception_message) { /code: 500/ }
+        let(:exception_message) { %r{code: 500} }
 
         include_examples 'failed attempt'
       end
diff --git a/spec/lib/html_sanitizer_spec.rb b/spec/lib/html_sanitizer_spec.rb
index e387178cb..7f1d0628d 100644
--- a/spec/lib/html_sanitizer_spec.rb
+++ b/spec/lib/html_sanitizer_spec.rb
@@ -24,7 +24,7 @@ RSpec.describe HtmlSanitizer do
         let(:html) { '<img style="width: 181px; height: 125px" src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/...">' }
 
         it 'converts embedded image to cid' do
-          expect(body).to match(/<img style="width: 181px; height: 125px" src="cid:.+?">/)
+          expect(body).to match(%r{<img style="width: 181px; height: 125px" src="cid:.+?">})
         end
 
         it 'extracts one attachment' do
@@ -40,7 +40,7 @@ RSpec.describe HtmlSanitizer do
         end
 
         it 'sets Content-ID based on Zammad fqdn' do
-          expect(inline_attachments.first[:preferences]['Content-ID']).to match(/@#{Setting.get('fqdn')}/)
+          expect(inline_attachments.first[:preferences]['Content-ID']).to match(%r{@#{Setting.get('fqdn')}})
         end
 
         it 'sets Content-Disposition to inline' do
@@ -52,7 +52,7 @@ RSpec.describe HtmlSanitizer do
         let(:html) { '<img src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/..." style="width: 181px; height: 125px" alt="abc">' }
 
         it 'converts embedded image to cid' do
-          expect(body).to match(/<img src="cid:.+?" style="width: 181px; height: 125px" alt="abc">/)
+          expect(body).to match(%r{<img src="cid:.+?" style="width: 181px; height: 125px" alt="abc">})
         end
 
         it 'extracts one attachment' do
@@ -68,7 +68,7 @@ RSpec.describe HtmlSanitizer do
         end
 
         it 'sets Content-ID based on Zammad fqdn' do
-          expect(inline_attachments.first[:preferences]['Content-ID']).to match(/@#{Setting.get('fqdn')}/)
+          expect(inline_attachments.first[:preferences]['Content-ID']).to match(%r{@#{Setting.get('fqdn')}})
         end
 
         it 'sets Content-Disposition to inline' do
@@ -80,7 +80,7 @@ RSpec.describe HtmlSanitizer do
         let(:html) { '<img src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/..." style="width: 181px; height: 125px" alt="abc"><invalid what ever' }
 
         it 'converts embedded image to cid' do
-          expect(body).to match(/<img src="cid:.+?" style="width: 181px; height: 125px" alt="abc">/)
+          expect(body).to match(%r{<img src="cid:.+?" style="width: 181px; height: 125px" alt="abc">})
         end
 
         it 'extracts one attachment' do
@@ -96,7 +96,7 @@ RSpec.describe HtmlSanitizer do
         end
 
         it 'sets Content-ID based on Zammad fqdn' do
-          expect(inline_attachments.first[:preferences]['Content-ID']).to match(/@#{Setting.get('fqdn')}/)
+          expect(inline_attachments.first[:preferences]['Content-ID']).to match(%r{@#{Setting.get('fqdn')}})
         end
 
         it 'sets Content-Disposition to inline' do
@@ -126,8 +126,8 @@ RSpec.describe HtmlSanitizer do
         end
 
         it 'sets Content-IDs based on Zammad fqdn' do
-          expect(inline_attachments.first[:preferences]['Content-ID']).to match(/@#{Setting.get('fqdn')}/)
-          expect(inline_attachments.second[:preferences]['Content-ID']).to match(/@#{Setting.get('fqdn')}/)
+          expect(inline_attachments.first[:preferences]['Content-ID']).to match(%r{@#{Setting.get('fqdn')}})
+          expect(inline_attachments.second[:preferences]['Content-ID']).to match(%r{@#{Setting.get('fqdn')}})
         end
 
         it 'sets Content-Dispositions to inline' do
diff --git a/spec/lib/import/zendesk/object_attribute/base_examples.rb b/spec/lib/import/zendesk/object_attribute/base_examples.rb
index 451b9ba70..81d59d01e 100644
--- a/spec/lib/import/zendesk/object_attribute/base_examples.rb
+++ b/spec/lib/import/zendesk/object_attribute/base_examples.rb
@@ -25,7 +25,7 @@ RSpec.shared_examples Import::Zendesk::ObjectAttribute::Base do
 
       expect do
         described_class.new('Ticket', 'example_field', attribute)
-      end.to raise_error(RuntimeError, /'example_field': #{error_text}$/)
+      end.to raise_error(RuntimeError, %r{'example_field': #{error_text}$})
     end
   end
 
diff --git a/spec/lib/ldap/user_spec.rb b/spec/lib/ldap/user_spec.rb
index ad9deef6f..fb8968225 100644
--- a/spec/lib/ldap/user_spec.rb
+++ b/spec/lib/ldap/user_spec.rb
@@ -204,7 +204,7 @@ RSpec.describe Ldap::User do
   # stored in test/data/tcr_cassettes.
   context 'on mocked LDAP connections' do
     around do |example|
-      cassette_name = example.description.gsub(/[^0-9A-Za-z.\-]+/, '_')
+      cassette_name = example.description.gsub(%r{[^0-9A-Za-z.\-]+}, '_')
 
       begin
         original_tcr_format = TCR.configuration.format
diff --git a/spec/lib/notification_factory/slack_spec.rb b/spec/lib/notification_factory/slack_spec.rb
index cbe620939..11140fd82 100644
--- a/spec/lib/notification_factory/slack_spec.rb
+++ b/spec/lib/notification_factory/slack_spec.rb
@@ -33,8 +33,8 @@ RSpec.describe NotificationFactory::Slack do
 
       it 'returns a hash with body: <article author & body>' do
         expect(template[:body])
-          .to match(/Created by #{current_user.fullname}/)
-          .and match(/#{article.body}\z/)
+          .to match(%r{Created by #{current_user.fullname}})
+          .and match(%r{#{article.body}\z})
       end
     end
 
@@ -55,11 +55,11 @@ RSpec.describe NotificationFactory::Slack do
 
       it 'returns a hash with body: <article editor, changes, & body>' do
         expect(template[:body])
-          .to match(/Updated by #{current_user.fullname}/)
-          .and match(/state: aaa -> bbb/)
-          .and match(/group: xxx -> yyy/)
+          .to match(%r{Updated by #{current_user.fullname}})
+          .and match(%r{state: aaa -> bbb})
+          .and match(%r{group: xxx -> yyy})
           .and match(%r{pending_time: 04/01/2019 12:00 \(Europe/Berlin\) -> 04/02/2019 01:00 \(Europe/Berlin\)})
-          .and match(/#{article.body}\z/)
+          .and match(%r{#{article.body}\z})
       end
     end
 
@@ -87,9 +87,9 @@ RSpec.describe NotificationFactory::Slack do
 
       it 'returns a hash with body: <ticket customer, escalation time, & body>' do
         expect(template[:body])
-          .to match(/A ticket \(#{ticket.title}\) from "#{ticket.customer.fullname}"/)
+          .to match(%r{A ticket \(#{ticket.title}\) from "#{ticket.customer.fullname}"})
           .and match(%r{is escalated since "04/01/2019 12:00 \(Europe/Berlin\)"!})
-          .and match(/#{article.body}\z/)
+          .and match(%r{#{article.body}\z})
       end
     end
   end
diff --git a/spec/lib/secure_mailing/smime_spec.rb b/spec/lib/secure_mailing/smime_spec.rb
index 7af7f08cc..a7cdd5308 100644
--- a/spec/lib/secure_mailing/smime_spec.rb
+++ b/spec/lib/secure_mailing/smime_spec.rb
@@ -470,7 +470,7 @@ RSpec.describe SecureMailing::SMIME do
               expect(mail['x-zammad-article-preferences'][:security][:encryption][:success]).to be false
               expect(mail['x-zammad-article-preferences'][:security][:encryption][:comment]).to be nil
 
-              expect(Rails.logger).not_to have_received(:warn).with(/#{Regexp.escape(ca_certificate_subject)}/)
+              expect(Rails.logger).not_to have_received(:warn).with(%r{#{Regexp.escape(ca_certificate_subject)}})
             end
           end
         end
diff --git a/spec/lib/sequencer/unit/import/common/mapping/flat_keys_spec.rb b/spec/lib/sequencer/unit/import/common/mapping/flat_keys_spec.rb
index c9bbb1a32..ee9ca6bb9 100644
--- a/spec/lib/sequencer/unit/import/common/mapping/flat_keys_spec.rb
+++ b/spec/lib/sequencer/unit/import/common/mapping/flat_keys_spec.rb
@@ -9,7 +9,7 @@ RSpec.describe Sequencer::Unit::Import::Common::Mapping::FlatKeys, sequencer: :u
           remote_attribute: 'value',
         }
       )
-    end.to raise_error(RuntimeError, /mapping/)
+    end.to raise_error(RuntimeError, %r{mapping})
   end
 
   it 'maps flat key structures' do
diff --git a/spec/lib/static_assets_spec.rb b/spec/lib/static_assets_spec.rb
index ee9c05f29..c72ef7499 100644
--- a/spec/lib/static_assets_spec.rb
+++ b/spec/lib/static_assets_spec.rb
@@ -3,11 +3,11 @@ require 'rails_helper'
 RSpec.describe StaticAssets do
   describe '.data_url_attributes' do
     it 'raises error if empty string given' do
-      expect { described_class.data_url_attributes('') }.to raise_error(/Unable to parse data url/)
+      expect { described_class.data_url_attributes('') }.to raise_error(%r{Unable to parse data url})
     end
 
     it 'raises error if nil' do
-      expect { described_class.data_url_attributes(nil) }.to raise_error(/Unable to parse data url/)
+      expect { described_class.data_url_attributes(nil) }.to raise_error(%r{Unable to parse data url})
     end
   end
 end
diff --git a/spec/models/channel/driver/twitter_spec.rb b/spec/models/channel/driver/twitter_spec.rb
index 3c4907371..b24f48732 100644
--- a/spec/models/channel/driver/twitter_spec.rb
+++ b/spec/models/channel/driver/twitter_spec.rb
@@ -901,8 +901,8 @@ RSpec.describe Channel::Driver::Twitter do
           it 'creates articles for parent tweets as well' do
             channel.fetch
 
-            expect(thread.articles.last.body).to match(/zammad/i)       # search result
-            expect(thread.articles.first.body).not_to match(/zammad/i)  # parent tweet
+            expect(thread.articles.last.body).to match(%r{zammad}i)       # search result
+            expect(thread.articles.first.body).not_to match(%r{zammad}i)  # parent tweet
           end
         end
 
diff --git a/spec/models/channel/email_parser_spec.rb b/spec/models/channel/email_parser_spec.rb
index 080431fe3..ca819792f 100644
--- a/spec/models/channel/email_parser_spec.rb
+++ b/spec/models/channel/email_parser_spec.rb
@@ -1159,7 +1159,7 @@ RSpec.describe Channel::EmailParser, type: :model do
     context 'for “delivery failed” notifications (a.k.a. bounce messages)' do
       let(:ticket) { article.ticket }
       let(:article) { create(:ticket_article, sender_name: 'Agent', message_id: message_id) }
-      let(:message_id) { raw_mail[/(?<=^(References|Message-ID): )\S*/] }
+      let(:message_id) { raw_mail[%r{(?<=^(References|Message-ID): )\S*}] }
 
       context 'with future retries (delayed)' do
         let(:mail_file) { Rails.root.join('test/data/mail/mail078.box') }
@@ -1347,7 +1347,7 @@ RSpec.describe Channel::EmailParser, type: :model do
 
             Postmaster of zammad.example.com
           BODY
-          body.gsub(/\n/, "\r\n")
+          body.gsub(%r{\n}, "\r\n")
         end
       end
     end
@@ -1370,7 +1370,7 @@ RSpec.describe Channel::EmailParser, type: :model do
 
             Postmaster von zammad.example.com
           BODY
-          body.gsub(/\n/, "\r\n")
+          body.gsub(%r{\n}, "\r\n")
         end
       end
     end
diff --git a/spec/models/channel/filter/internal_article_check_spec.rb b/spec/models/channel/filter/internal_article_check_spec.rb
index 27181534b..33e4cc214 100644
--- a/spec/models/channel/filter/internal_article_check_spec.rb
+++ b/spec/models/channel/filter/internal_article_check_spec.rb
@@ -21,7 +21,7 @@ RSpec.describe Channel::Filter::InternalArticleCheck do
   let(:email_parse_mail_answer) do
     channel_as_model = Channel.new(options: {})
 
-    email_raw_string.sub!(/^Subject: .+?$/, subject)
+    email_raw_string.sub!(%r{^Subject: .+?$}, subject)
     email_raw_string.sub!('From: <John.Smith@example.com>', from)
     email_raw_string.sub!('Message-Id: <053EA3703574649ABDAF24D43A05604F327A130@MEMASFRK004.example.com>', "Message-Id: <053EA3703574649ABDAF24D43A05604F327A130@MEMASFRK004.example.com>\nIn-Reply-To: #{in_reply_to}")
     Channel::EmailParser.new.process(channel_as_model, email_raw_string)
diff --git a/spec/models/channel_spec.rb b/spec/models/channel_spec.rb
index bafe1f696..c8ecec4ff 100644
--- a/spec/models/channel_spec.rb
+++ b/spec/models/channel_spec.rb
@@ -86,7 +86,7 @@ RSpec.describe Channel, type: :model do
         end
 
         it 'raises RuntimeError' do
-          expect { channel.refresh_xoauth2! }.to raise_exception(RuntimeError, /#{exception.message}/)
+          expect { channel.refresh_xoauth2! }.to raise_exception(RuntimeError, %r{#{exception.message}})
         end
       end
 
diff --git a/spec/models/cti/log_spec.rb b/spec/models/cti/log_spec.rb
index a5a1bdd37..4fd54b09b 100644
--- a/spec/models/cti/log_spec.rb
+++ b/spec/models/cti/log_spec.rb
@@ -161,7 +161,7 @@ RSpec.describe Cti::Log do
         before { create(:'cti/log', call_id: '1') }
 
         it 'raises an error' do
-          expect { described_class.process(attributes) }.to raise_error(/call_id \S+ already exists!/)
+          expect { described_class.process(attributes) }.to raise_error(%r{call_id \S+ already exists!})
         end
       end
     end
@@ -171,7 +171,7 @@ RSpec.describe Cti::Log do
 
       context 'with unrecognized "call_id"' do
         it 'raises an error' do
-          expect { described_class.process(attributes) }.to raise_error(/No such call_id/)
+          expect { described_class.process(attributes) }.to raise_error(%r{No such call_id})
         end
       end
 
@@ -202,7 +202,7 @@ RSpec.describe Cti::Log do
 
       context 'with unrecognized "call_id"' do
         it 'raises an error' do
-          expect { described_class.process(attributes) }.to raise_error(/No such call_id/)
+          expect { described_class.process(attributes) }.to raise_error(%r{No such call_id})
         end
       end
 
diff --git a/spec/models/knowledge_base/answer/translation_spec.rb b/spec/models/knowledge_base/answer/translation_spec.rb
index 530d002b4..603e8522f 100644
--- a/spec/models/knowledge_base/answer/translation_spec.rb
+++ b/spec/models/knowledge_base/answer/translation_spec.rb
@@ -7,7 +7,7 @@ RSpec.describe KnowledgeBase::Answer::Translation, type: :model, current_user_id
   include_context 'factory'
 
   it { is_expected.to validate_presence_of(:title) }
-  it { is_expected.to validate_uniqueness_of(:kb_locale_id).scoped_to(:answer_id).with_message(//) }
+  it { is_expected.to validate_uniqueness_of(:kb_locale_id).scoped_to(:answer_id).with_message(%r{}) }
 
   it { is_expected.to belong_to(:answer) }
   it { is_expected.to belong_to(:kb_locale) }
diff --git a/spec/models/knowledge_base/category/translation_spec.rb b/spec/models/knowledge_base/category/translation_spec.rb
index 5980b568a..cd8e8f69e 100644
--- a/spec/models/knowledge_base/category/translation_spec.rb
+++ b/spec/models/knowledge_base/category/translation_spec.rb
@@ -7,7 +7,7 @@ RSpec.describe KnowledgeBase::Category::Translation, type: :model do
   include_context 'factory'
 
   it { is_expected.to validate_presence_of(:title) }
-  it { is_expected.to validate_uniqueness_of(:kb_locale_id).scoped_to(:category_id).with_message(//) }
+  it { is_expected.to validate_uniqueness_of(:kb_locale_id).scoped_to(:category_id).with_message(%r{}) }
 
   it { is_expected.to belong_to(:category) }
   it { is_expected.to belong_to(:kb_locale) }
diff --git a/spec/models/knowledge_base/translation_spec.rb b/spec/models/knowledge_base/translation_spec.rb
index d3f558585..eccc20a45 100644
--- a/spec/models/knowledge_base/translation_spec.rb
+++ b/spec/models/knowledge_base/translation_spec.rb
@@ -7,7 +7,7 @@ RSpec.describe KnowledgeBase::Translation, type: :model do
   include_context 'factory'
 
   it { is_expected.to validate_presence_of(:title) }
-  it { is_expected.to validate_uniqueness_of(:kb_locale_id).scoped_to(:knowledge_base_id).with_message(//) }
+  it { is_expected.to validate_uniqueness_of(:kb_locale_id).scoped_to(:knowledge_base_id).with_message(%r{}) }
 
   it { is_expected.to belong_to(:knowledge_base) }
   it { is_expected.to belong_to(:kb_locale) }
diff --git a/spec/models/knowledge_base_spec.rb b/spec/models/knowledge_base_spec.rb
index f6da2f16e..31b2b45e8 100644
--- a/spec/models/knowledge_base_spec.rb
+++ b/spec/models/knowledge_base_spec.rb
@@ -14,7 +14,7 @@ RSpec.describe KnowledgeBase, type: :model do
 
   it { is_expected.to validate_presence_of(:color_highlight) }
   it { is_expected.to validate_presence_of(:color_header) }
-  it { is_expected.to validate_presence_of(:iconset).with_message(//) }
+  it { is_expected.to validate_presence_of(:iconset).with_message(%r{}) }
   it { is_expected.to validate_inclusion_of(:iconset).in_array(KnowledgeBase::ICONSETS) }
   it { is_expected.to validate_inclusion_of(:category_layout).in_array(KnowledgeBase::LAYOUTS) }
   it { is_expected.to validate_inclusion_of(:homepage_layout).in_array(KnowledgeBase::LAYOUTS) }
diff --git a/spec/models/object_manager/attribute_spec.rb b/spec/models/object_manager/attribute_spec.rb
index 870d59993..cac8d5eab 100644
--- a/spec/models/object_manager/attribute_spec.rb
+++ b/spec/models/object_manager/attribute_spec.rb
@@ -62,7 +62,7 @@ RSpec.describe ObjectManager::Attribute, type: :model do
       it "rejects Zammad reserved word '#{reserved_word}'" do
         expect do
           described_class.add attributes_for :object_manager_attribute_text, name: reserved_word
-        end.to raise_error(ActiveRecord::RecordInvalid, /is a reserved word! \(1\)/)
+        end.to raise_error(ActiveRecord::RecordInvalid, %r{is a reserved word! \(1\)})
       end
     end
 
diff --git a/spec/models/overview_spec.rb b/spec/models/overview_spec.rb
index 081f6235b..d1c1e96ee 100644
--- a/spec/models/overview_spec.rb
+++ b/spec/models/overview_spec.rb
@@ -46,7 +46,7 @@ RSpec.describe Overview, type: :model do
 
       it 'handles special chars' do
         overview = create(:overview, name: 'Д дФ ф')
-        expect(overview.link).to match(/^\d{1,3}$/)
+        expect(overview.link).to match(%r{^\d{1,3}$})
       end
 
       it 'removes special char fallback if possible' do
diff --git a/spec/models/role_spec.rb b/spec/models/role_spec.rb
index 94b118aa3..023c16f79 100644
--- a/spec/models/role_spec.rb
+++ b/spec/models/role_spec.rb
@@ -72,13 +72,13 @@ RSpec.describe Role do
 
         it 'cannot be created' do
           expect { create(:role, permissions: [permission]) }
-            .to raise_error(/is disabled/)
+            .to raise_error(%r{is disabled})
             .and change(described_class, :count).by(0)
         end
 
         it 'cannot be added' do
           expect { role.permissions << permission }
-            .to raise_error(/is disabled/)
+            .to raise_error(%r{is disabled})
             .and change { role.permissions.count }.by(0)
         end
       end
@@ -88,7 +88,7 @@ RSpec.describe Role do
 
         it 'cannot be created' do
           expect { create(:role, permissions: [Permission.first, permission]) }
-            .to raise_error(/conflicts with/)
+            .to raise_error(%r{conflicts with})
             .and change(described_class, :count).by(0)
         end
 
@@ -96,7 +96,7 @@ RSpec.describe Role do
           role.permissions << Permission.first
 
           expect { role.permissions << permission }
-            .to raise_error(/conflicts with/)
+            .to raise_error(%r{conflicts with})
             .and change { role.permissions.count }.by(0)
         end
       end
@@ -148,14 +148,14 @@ RSpec.describe Role do
           role.default_at_signup = true
 
           expect { role.save }
-            .to raise_error(Exceptions::UnprocessableEntity, /Cannot set default at signup/)
+            .to raise_error(Exceptions::UnprocessableEntity, %r{Cannot set default at signup})
         end
 
         it 'cannot be changed to true' do
           role.save
 
           expect { role.update(default_at_signup: true) }
-            .to raise_error(Exceptions::UnprocessableEntity, /Cannot set default at signup/)
+            .to raise_error(Exceptions::UnprocessableEntity, %r{Cannot set default at signup})
         end
       end
 
@@ -168,14 +168,14 @@ RSpec.describe Role do
           role.default_at_signup = true
 
           expect { role.save }
-            .to raise_error(Exceptions::UnprocessableEntity, /Cannot set default at signup/)
+            .to raise_error(Exceptions::UnprocessableEntity, %r{Cannot set default at signup})
         end
 
         it 'cannot be changed to true' do
           role.save
 
           expect { role.update(default_at_signup: true) }
-            .to raise_error(Exceptions::UnprocessableEntity, /Cannot set default at signup/)
+            .to raise_error(Exceptions::UnprocessableEntity, %r{Cannot set default at signup})
         end
       end
 
@@ -186,14 +186,14 @@ RSpec.describe Role do
           role.default_at_signup = true
 
           expect { role.save }
-            .to raise_error(Exceptions::UnprocessableEntity, /Cannot set default at signup/)
+            .to raise_error(Exceptions::UnprocessableEntity, %r{Cannot set default at signup})
         end
 
         it 'cannot be changed to true' do
           role.save
 
           expect { role.update(default_at_signup: true) }
-            .to raise_error(Exceptions::UnprocessableEntity, /Cannot set default at signup/)
+            .to raise_error(Exceptions::UnprocessableEntity, %r{Cannot set default at signup})
         end
       end
     end
diff --git a/spec/models/smime_certificate_spec.rb b/spec/models/smime_certificate_spec.rb
index 65e590356..c2cd84b8a 100644
--- a/spec/models/smime_certificate_spec.rb
+++ b/spec/models/smime_certificate_spec.rb
@@ -192,6 +192,6 @@ RSpec.describe SMIMECertificate, type: :model do
   end
 
   it 'ensures uniqueness of records' do
-    expect { create_list(:smime_certificate, 2, fixture: 'smime1@example.com') }.to raise_error(ActiveRecord::RecordInvalid, /Validation failed/)
+    expect { create_list(:smime_certificate, 2, fixture: 'smime1@example.com') }.to raise_error(ActiveRecord::RecordInvalid, %r{Validation failed})
   end
 end
diff --git a/spec/models/ticket/number/increment_spec.rb b/spec/models/ticket/number/increment_spec.rb
index 01a76f96f..3085476b4 100644
--- a/spec/models/ticket/number/increment_spec.rb
+++ b/spec/models/ticket/number/increment_spec.rb
@@ -24,12 +24,12 @@ RSpec.describe Ticket::Number::Increment do
           before { Setting.set('system_id', 123_456) }
 
           it 'still adheres to numbering pattern (and does not require padding zeroes)' do
-            expect(number).to match(/^#{system_id}#{ticket_count}$/)
+            expect(number).to match(%r{^#{system_id}#{ticket_count}$})
           end
         end
 
         it 'returns a string following the pattern system_id + padding zeroes + ticket_count' do
-          expect(number).to match(/^#{system_id}0*#{ticket_count}$/)
+          expect(number).to match(%r{^#{system_id}0*#{ticket_count}$})
         end
 
         context '/ checksum: false (default)' do
@@ -41,14 +41,14 @@ RSpec.describe Ticket::Number::Increment do
           end
 
           it 'returns a string following the pattern system_id + padding zeroes + ticket_counter' do
-            expect(number).to match(/^#{system_id}0*#{ticket_count}$/)
+            expect(number).to match(%r{^#{system_id}0*#{ticket_count}$})
           end
 
           context 'when "system_id" setting exceeds :min_size' do
             before { Setting.set('system_id', 123_456) }
 
             it 'still adheres to numbering pattern (and does not require padding zeroes)' do
-              expect(number).to match(/^#{system_id}#{ticket_count}$/)
+              expect(number).to match(%r{^#{system_id}#{ticket_count}$})
             end
           end
         end
@@ -63,14 +63,14 @@ RSpec.describe Ticket::Number::Increment do
           end
 
           it 'returns a string following the pattern system_id + padding zeroes + ticket_counter + checksum' do
-            expect(number).to match(/^#{system_id}0*#{ticket_count}\d$/)
+            expect(number).to match(%r{^#{system_id}0*#{ticket_count}\d$})
           end
 
           context 'when "system_id" setting exceeds :min_size' do
             before { Setting.set('system_id', 123_456) }
 
             it 'still adheres to numbering pattern (and does not require padding zeroes)' do
-              expect(number).to match(/^#{system_id}#{ticket_count}\d$/)
+              expect(number).to match(%r{^#{system_id}#{ticket_count}\d$})
             end
           end
         end
diff --git a/spec/models/trigger/sms_spec.rb b/spec/models/trigger/sms_spec.rb
index bc5967078..1ab0ce0a7 100644
--- a/spec/models/trigger/sms_spec.rb
+++ b/spec/models/trigger/sms_spec.rb
@@ -42,7 +42,7 @@ RSpec.describe Trigger do
       end
 
       it 'renders HTML chars' do
-        expect(triggered_article.body).to match(/space between/)
+        expect(triggered_article.body).to match(%r{space between})
       end
 
       it 'interpolates ticket properties' do
diff --git a/spec/models/trigger_spec.rb b/spec/models/trigger_spec.rb
index cf0bc1eb9..f7a246c60 100644
--- a/spec/models/trigger_spec.rb
+++ b/spec/models/trigger_spec.rb
@@ -452,8 +452,8 @@ RSpec.describe Trigger, type: :model do
           let!(:article) do
             create(:ticket_article,
                    ticket:     ticket,
-                   message_id: raw_email[/(?<=^References: )\S*/],
-                   subject:    raw_email[/(?<=^Subject: Re: ).*$/])
+                   message_id: raw_email[%r{(?<=^References: )\S*}],
+                   subject:    raw_email[%r{(?<=^Subject: Re: ).*$}])
           end
 
           let(:raw_email) { File.read(Rails.root.join('test/data/mail/mail005.box')) }
@@ -470,7 +470,7 @@ RSpec.describe Trigger, type: :model do
           let!(:article) do
             create(:ticket_article,
                    ticket:     ticket,
-                   message_id: raw_email[/(?<=^Message-ID: )\S*/])
+                   message_id: raw_email[%r{(?<=^Message-ID: )\S*}])
           end
 
           let(:raw_email) { File.read(Rails.root.join('test/data/mail/mail055.box')) }
diff --git a/spec/models/webhook_spec.rb b/spec/models/webhook_spec.rb
index 3846367c0..1b69f91f8 100644
--- a/spec/models/webhook_spec.rb
+++ b/spec/models/webhook_spec.rb
@@ -73,7 +73,7 @@ RSpec.describe Webhook, type: :model do
       let!(:trigger) { create(:trigger, perform: { 'notification.webhook' => { 'webhook_id' => webhook.id.to_s } }) }
 
       it 'raises error with details' do
-        expect { webhook.destroy }.to raise_error(Exceptions::UnprocessableEntity, /#{Regexp.escape("Trigger: #{trigger.name} (##{trigger.id})")}/)
+        expect { webhook.destroy }.to raise_error(Exceptions::UnprocessableEntity, %r{#{Regexp.escape("Trigger: #{trigger.name} (##{trigger.id})")}})
       end
     end
   end
diff --git a/spec/requests/api_auth_spec.rb b/spec/requests/api_auth_spec.rb
index e924b151a..3856f069d 100644
--- a/spec/requests/api_auth_spec.rb
+++ b/spec/requests/api_auth_spec.rb
@@ -39,7 +39,7 @@ RSpec.describe 'Api Auth', type: :request do
       get '/api/v1/sessions', params: {}, as: :json
       expect(response).to have_http_status(:ok)
       expect(response.header['Access-Control-Allow-Origin']).to eq('*')
-      expect(response.header['Cache-Control']).to match(/no-cache, no-store/)
+      expect(response.header['Cache-Control']).to match(%r{no-cache, no-store})
       expect(response.header['Pragma']).to eq('no-cache')
       expect(response.header['Expires']).to eq('-1')
       expect(json_response).to be_a_kind_of(Hash)
@@ -60,7 +60,7 @@ RSpec.describe 'Api Auth', type: :request do
       get '/api/v1/tickets', params: {}, as: :json
       expect(response).to have_http_status(:ok)
       expect(response.header['Access-Control-Allow-Origin']).to eq('*')
-      expect(response.header['Cache-Control']).to match(/no-cache, no-store/)
+      expect(response.header['Cache-Control']).to match(%r{no-cache, no-store})
       expect(response.header['Pragma']).to eq('no-cache')
       expect(response.header['Expires']).to eq('-1')
       expect(json_response).to be_a_kind_of(Array)
@@ -81,7 +81,7 @@ RSpec.describe 'Api Auth', type: :request do
       get '/api/v1/tickets', params: {}, as: :json
       expect(response).to have_http_status(:ok)
       expect(response.header['Access-Control-Allow-Origin']).to eq('*')
-      expect(response.header['Cache-Control']).to match(/no-cache, no-store/)
+      expect(response.header['Cache-Control']).to match(%r{no-cache, no-store})
       expect(response.header['Pragma']).to eq('no-cache')
       expect(response.header['Expires']).to eq('-1')
       expect(json_response).to be_a_kind_of(Array)
@@ -113,7 +113,7 @@ RSpec.describe 'Api Auth', type: :request do
       get '/api/v1/sessions', params: {}, as: :json
       expect(response).to have_http_status(:ok)
       expect(response.header['Access-Control-Allow-Origin']).to eq('*')
-      expect(response.header['Cache-Control']).to match(/no-cache, no-store/)
+      expect(response.header['Cache-Control']).to match(%r{no-cache, no-store})
       expect(response.header['Pragma']).to eq('no-cache')
       expect(response.header['Expires']).to eq('-1')
 
@@ -263,7 +263,7 @@ RSpec.describe 'Api Auth', type: :request do
       get '/api/v1/tickets', params: {}, as: :json
       expect(response).to have_http_status(:ok)
       expect(response.header['Access-Control-Allow-Origin']).to eq('*')
-      expect(response.header['Cache-Control']).to match(/no-cache, no-store/)
+      expect(response.header['Cache-Control']).to match(%r{no-cache, no-store})
       expect(response.header['Pragma']).to eq('no-cache')
       expect(response.header['Expires']).to eq('-1')
       expect(json_response).to be_a_kind_of(Array)
@@ -301,7 +301,7 @@ RSpec.describe 'Api Auth', type: :request do
       Setting.set('api_token_access', true)
       get '/api/v1/tickets', params: {}, as: :json
       expect(response.header['Access-Control-Allow-Origin']).to eq('*')
-      expect(response.header['Cache-Control']).to match(/no-cache, no-store/)
+      expect(response.header['Cache-Control']).to match(%r{no-cache, no-store})
       expect(response.header['Pragma']).to eq('no-cache')
       expect(response.header['Expires']).to eq('-1')
       expect(response).to have_http_status(:ok)
@@ -388,7 +388,7 @@ RSpec.describe 'Api Auth', type: :request do
       get '/api/v1/tickets', params: {}, as: :json
       expect(response).to have_http_status(:ok)
       expect(response.header['Access-Control-Allow-Origin']).to eq('*')
-      expect(response.header['Cache-Control']).to match(/no-cache, no-store/)
+      expect(response.header['Cache-Control']).to match(%r{no-cache, no-store})
       expect(response.header['Pragma']).to eq('no-cache')
       expect(response.header['Expires']).to eq('-1')
       expect(json_response).to be_a_kind_of(Array)
diff --git a/spec/requests/channels_twitter_spec.rb b/spec/requests/channels_twitter_spec.rb
index 129edadb8..e456bfcb7 100644
--- a/spec/requests/channels_twitter_spec.rb
+++ b/spec/requests/channels_twitter_spec.rb
@@ -46,7 +46,7 @@ RSpec.describe 'Twitter channel API endpoints', type: :request do
   end
 
   describe 'POST /api/v1/channels_twitter_webhook' do
-    let(:payload) { params.stringify_keys.to_s.gsub(/=>/, ':').delete(' ') }
+    let(:payload) { params.stringify_keys.to_s.gsub(%r{=>}, ':').delete(' ') }
     let(:headers) { { 'x-twitter-webhooks-signature': hash_signature } }
     let(:params) { { foo: 'bar', for_user_id: twitter_channel.options[:user][:id] } }
 
diff --git a/spec/requests/external_credentials_spec.rb b/spec/requests/external_credentials_spec.rb
index ceaf4ae3b..9252feed0 100644
--- a/spec/requests/external_credentials_spec.rb
+++ b/spec/requests/external_credentials_spec.rb
@@ -372,7 +372,7 @@ RSpec.describe 'External Credentials', type: :request do
 
             expect(WebMock)
               .to have_requested(:post, 'https://api.twitter.com/oauth/request_token')
-              .with(headers: { 'Authorization' => /oauth_consumer_key="#{twitter_credential.credentials[:consumer_key]}"/ } )
+              .with(headers: { 'Authorization' => %r{oauth_consumer_key="#{twitter_credential.credentials[:consumer_key]}"} } )
           end
 
           it 'redirects to Twitter authorization URL' do
diff --git a/spec/requests/integration/telegram_spec.rb b/spec/requests/integration/telegram_spec.rb
index a67216021..dfe387505 100644
--- a/spec/requests/integration/telegram_spec.rb
+++ b/spec/requests/integration/telegram_spec.rb
@@ -181,7 +181,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           post callback_url, params: read_message('private', 'document'), as: :json
           expect(response).to have_http_status(:ok)
           ticket = Ticket.last
-          expect(ticket.articles.last.body).to match(/<img style="width:200px;height:200px;"/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="width:200px;height:200px;"}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
           expect(ticket.articles.last.attachments.count).to eq(1)
           expect(Store.last.filename).to eq('document.pdf')
@@ -191,7 +191,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           post callback_url, params: read_message('private', 'photo'), as: :json
           expect(response).to have_http_status(:ok)
           ticket = Ticket.last
-          expect(ticket.articles.last.body).to match(/<img style="width:360px;height:327px;"/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="width:360px;height:327px;"}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
         end
 
@@ -200,7 +200,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           expect(response).to have_http_status(:ok)
           ticket = Ticket.last
           expect(ticket.articles.count).to eq(1)
-          expect(ticket.articles.last.body).to match(/<img style="/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
           expect(ticket.articles.last.attachments.count).to eq(1)
           expect(Store.last.filename).to eq('video-videofileid.mp4')
@@ -218,7 +218,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           end
           expect(ticket.state.name).to eq('new')
           expect(ticket.articles.count).to eq(1)
-          expect(ticket.articles.last.body).to match(/<img style="/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
           expect(ticket.articles.last.attachments.count).to eq(1)
           expect(Store.last.filename).to eq('HotCherry.webp')
@@ -287,7 +287,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           post callback_url, params: read_message('channel', 'document'), as: :json
           expect(response).to have_http_status(:ok)
           ticket = Ticket.last
-          expect(ticket.articles.last.body).to match(/<img style="width:200px;height:200px;"/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="width:200px;height:200px;"}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
           expect(ticket.articles.last.attachments.count).to eq(1)
           expect(Store.last.filename).to eq('document.pdf')
@@ -297,7 +297,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           post callback_url, params: read_message('channel', 'photo'), as: :json
           expect(response).to have_http_status(:ok)
           ticket = Ticket.last
-          expect(ticket.articles.last.body).to match(/<img style="width:360px;height:327px;"/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="width:360px;height:327px;"}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
         end
 
@@ -306,7 +306,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           expect(response).to have_http_status(:ok)
           ticket = Ticket.last
           expect(ticket.articles.count).to eq(1)
-          expect(ticket.articles.last.body).to match(/<img style="/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
           expect(ticket.articles.last.attachments.count).to eq(1)
           expect(Store.last.filename).to eq('video-videofileid.mp4')
@@ -324,7 +324,7 @@ RSpec.describe 'Telegram Webhook Integration', type: :request do
           end
           expect(ticket.state.name).to eq('new')
           expect(ticket.articles.count).to eq(1)
-          expect(ticket.articles.last.body).to match(/<img style="/i)
+          expect(ticket.articles.last.body).to match(%r{<img style="}i)
           expect(ticket.articles.last.content_type).to eq('text/html')
           expect(ticket.articles.last.attachments.count).to eq(1)
           expect(Store.last.filename).to eq('HotCherry.webp')
diff --git a/spec/requests/ticket/article_attachments_spec.rb b/spec/requests/ticket/article_attachments_spec.rb
index b4a964dc9..9ec22a4b4 100644
--- a/spec/requests/ticket/article_attachments_spec.rb
+++ b/spec/requests/ticket/article_attachments_spec.rb
@@ -34,7 +34,7 @@ RSpec.describe 'Ticket Article Attachments', type: :request do
       authenticated_as(agent)
       get "/api/v1/ticket_attachment/#{ticket1.id}/#{article2.id}/#{store1.id}", params: {}
       expect(response).to have_http_status(:forbidden)
-      expect(@response.body).to match(/403: Forbidden/)
+      expect(@response.body).to match(%r{403: Forbidden})
 
       ticket2 = create(:ticket, group: group)
       ticket1.merge_to(
@@ -50,7 +50,7 @@ RSpec.describe 'Ticket Article Attachments', type: :request do
       authenticated_as(agent)
       get "/api/v1/ticket_attachment/#{ticket2.id}/#{article2.id}/#{store1.id}", params: {}
       expect(response).to have_http_status(:forbidden)
-      expect(@response.body).to match(/403: Forbidden/)
+      expect(@response.body).to match(%r{403: Forbidden})
 
       # allow access via merged ticket id also
       authenticated_as(agent)
@@ -61,7 +61,7 @@ RSpec.describe 'Ticket Article Attachments', type: :request do
       authenticated_as(agent)
       get "/api/v1/ticket_attachment/#{ticket1.id}/#{article2.id}/#{store1.id}", params: {}
       expect(response).to have_http_status(:forbidden)
-      expect(@response.body).to match(/403: Forbidden/)
+      expect(@response.body).to match(%r{403: Forbidden})
 
     end
 
diff --git a/spec/requests/ticket/article_spec.rb b/spec/requests/ticket/article_spec.rb
index 6c8929d7e..4e1a6046d 100644
--- a/spec/requests/ticket/article_spec.rb
+++ b/spec/requests/ticket/article_spec.rb
@@ -61,7 +61,7 @@ AAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO
       expect(response).to have_http_status(:created)
       expect(json_response).to be_a_kind_of(Hash)
       expect(json_response['subject']).to be_nil
-      expect(json_response['body']).not_to match(/some body <img src="cid:.+?/)
+      expect(json_response['body']).not_to match(%r{some body <img src="cid:.+?})
       expect(json_response['body']).to match(%r{some body <img src="/api/v1/ticket_attachment/.+?" alt="Red dot"})
       expect(json_response['content_type']).to eq('text/html')
       expect(json_response['updated_by_id']).to eq(agent.id)
@@ -76,7 +76,7 @@ AAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO
       expect(ticket.articles[2].attachments[0]['size']).to eq('21')
       expect(ticket.articles[2].attachments[0]['preferences']['Mime-Type']).to eq('image/png')
       expect(ticket.articles[2].attachments[0]['preferences']['Content-Disposition']).to eq('inline')
-      expect(ticket.articles[2].attachments[0]['preferences']['Content-ID']).to match(/@zammad.example.com/)
+      expect(ticket.articles[2].attachments[0]['preferences']['Content-ID']).to match(%r{@zammad.example.com})
 
       params = {
         ticket_id:    json_response['ticket_id'],
diff --git a/spec/requests/ticket/escalation_spec.rb b/spec/requests/ticket/escalation_spec.rb
index 3a63ac0a0..aae179175 100644
--- a/spec/requests/ticket/escalation_spec.rb
+++ b/spec/requests/ticket/escalation_spec.rb
@@ -18,7 +18,7 @@ RSpec.describe 'Ticket Escalation', type: :request do
 
   define :json_equal_date do
     match do
-      actual&.sub(/.\d\d\dZ$/, 'Z') == expected&.iso8601
+      actual&.sub(%r{.\d\d\dZ$}, 'Z') == expected&.iso8601
     end
   end
 
diff --git a/spec/requests/ticket_spec.rb b/spec/requests/ticket_spec.rb
index 2bc4b1ba6..fe2a689d4 100644
--- a/spec/requests/ticket_spec.rb
+++ b/spec/requests/ticket_spec.rb
@@ -699,13 +699,13 @@ RSpec.describe 'Ticket', type: :request do
       expect(Digest::MD5.hexdigest(file.content)).to eq('d3c1e09bdefb92b6a06b791a24ca9599')
       expect(file.filename).to eq('image1.png')
       expect(file.preferences['Mime-Type']).to eq('image/png')
-      expect(file.preferences['Content-ID']).to match(/#{ticket.id}\..+?@zammad.example.com/)
+      expect(file.preferences['Content-ID']).to match(%r{#{ticket.id}\..+?@zammad.example.com})
       expect(file.preferences['Content-ID']).to be_truthy
       file = ticket.articles.first.attachments[1]
       expect(Digest::MD5.hexdigest(file.content)).to eq('006a2ca3793b550c8fe444acdeb39252')
       expect(file.filename).to eq('image2.jpeg')
       expect(file.preferences['Mime-Type']).to eq('image/jpeg')
-      expect(file.preferences['Content-ID']).to match(/#{ticket.id}\..+?@zammad.example.com/)
+      expect(file.preferences['Content-ID']).to match(%r{#{ticket.id}\..+?@zammad.example.com})
       expect(file.preferences['Content-ID']).to be_truthy
     end
 
@@ -744,7 +744,7 @@ RSpec.describe 'Ticket', type: :request do
       expect(file.filename).to eq('image1.jpeg')
       expect(file.preferences['Mime-Type']).to eq('image/jpeg')
       expect(file.preferences['Content-ID']).to be_truthy
-      expect(file.preferences['Content-ID']).to match(/#{ticket.id}\..+?@zammad.example.com/)
+      expect(file.preferences['Content-ID']).to match(%r{#{ticket.id}\..+?@zammad.example.com})
       file = ticket.articles.first.attachments[1]
       expect(Digest::MD5.hexdigest(file.content)).to eq('39d0d586a701e199389d954f2d592720')
       expect(file.filename).to eq('some_file.txt')
diff --git a/spec/requests/user_spec.rb b/spec/requests/user_spec.rb
index c14975e54..abfeb27c2 100644
--- a/spec/requests/user_spec.rb
+++ b/spec/requests/user_spec.rb
@@ -168,7 +168,7 @@ RSpec.describe 'User', type: :request do
         params = { email: 'some_new_customer@example.com', password: 'asdasdasdasd', signup: true }
         post '/api/v1/users', params: params, headers: headers, as: :json
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(json_response['error']).to be_a(Array).and(include(match(/Invalid password/)))
+        expect(json_response['error']).to be_a(Array).and(include(match(%r{Invalid password})))
       end
 
       it 'verified with no current user', authenticated_as: :admin do
@@ -1442,12 +1442,12 @@ RSpec.describe 'User', type: :request do
 
     it 'returns verbose error when full image is missing' do
       make_request(avatar_full: '')
-      expect(json_response).to include('error' => match(/Full/).and(match(/is invalid/)))
+      expect(json_response).to include('error' => match(%r{Full}).and(match(%r{is invalid})))
     end
 
     it 'returns verbose error when resized image is missing' do
       make_request(avatar_full: base64)
-      expect(json_response).to include('error' => match(/Resized/).and(match(/is invalid/)))
+      expect(json_response).to include('error' => match(%r{Resized}).and(match(%r{is invalid})))
     end
 
     it 'successfully changes avatar' do
diff --git a/spec/support/assets_matchers.rb b/spec/support/assets_matchers.rb
index 4c4a6d300..61e02e80f 100644
--- a/spec/support/assets_matchers.rb
+++ b/spec/support/assets_matchers.rb
@@ -52,7 +52,7 @@ RSpec::Matchers.define :include_assets_of do
   #
   # @return [Hash, nil]
   def find_assets_of(object, actual)
-    actual.dig(object.class.name.gsub(/::/, ''), object.id.to_s)
+    actual.dig(object.class.name.gsub(%r{::}, ''), object.id.to_s)
   end
 end
 
diff --git a/spec/support/searchindex_backend.rb b/spec/support/searchindex_backend.rb
index c59d8612e..3b9be72f1 100644
--- a/spec/support/searchindex_backend.rb
+++ b/spec/support/searchindex_backend.rb
@@ -42,7 +42,7 @@ prepares elasticsearch
 
     if ENV['ES_INDEX_RAND'].present?
       rand_id          = ENV.fetch('CI_JOB_ID', "r#{rand(999)}")
-      test_method_name = self.class.description.gsub(/[^\w]/, '_')
+      test_method_name = self.class.description.gsub(%r{[^\w]}, '_')
       ENV['ES_INDEX']  = "es_index_#{test_method_name.downcase}_#{rand_id}_#{rand(999_999_999)}"
     end
     if ENV['ES_INDEX'].blank?
diff --git a/spec/support/vcr.rb b/spec/support/vcr.rb
index bc7d4e158..41fe39ce5 100644
--- a/spec/support/vcr.rb
+++ b/spec/support/vcr.rb
@@ -1,5 +1,5 @@
 VCR_IGNORE_MATCHING_HOSTS = %w[elasticsearch selenium zammad.org zammad.com znuny.com google.com login.microsoftonline.com github.com].freeze
-VCR_IGNORE_MATCHING_REGEXPS = [/^192\.168\.\d+\.\d+$/].freeze
+VCR_IGNORE_MATCHING_REGEXPS = [%r{^192\.168\.\d+\.\d+$}].freeze
 
 VCR.configure do |config|
   config.cassette_library_dir = 'test/data/vcr_cassettes'
@@ -14,7 +14,7 @@ VCR.configure do |config|
   end
 
   config.register_request_matcher(:oauth_headers) do |r1, r2|
-    without_onetime_oauth_params = ->(params) { params.gsub(/oauth_(nonce|signature|timestamp)="[^"]+", /, '') }
+    without_onetime_oauth_params = ->(params) { params.gsub(%r{oauth_(nonce|signature|timestamp)="[^"]+", }, '') }
 
     r1.headers.except('Authorization') == r2.headers.except('Authorization') &&
       r1.headers['Authorization']&.map(&without_onetime_oauth_params) ==
@@ -75,8 +75,8 @@ RSpec.configure do |config|
     vcr_options = Array(example.metadata[:use_vcr])
 
     spec_path       = Pathname.new(example.file_path).realpath
-    cassette_path   = spec_path.relative_path_from(Rails.root.join('spec')).sub(/_spec\.rb$/, '')
-    cassette_name   = "#{example.example_group.description} #{example.description}".gsub(/[^0-9A-Za-z.\-]+/, '_').downcase
+    cassette_path   = spec_path.relative_path_from(Rails.root.join('spec')).sub(%r{_spec\.rb$}, '')
+    cassette_name   = "#{example.example_group.description} #{example.description}".gsub(%r{[^0-9A-Za-z.\-]+}, '_').downcase
     request_profile = [
       :method,
       :uri,
diff --git a/spec/system/admin/knowledge_base/public_menu_spec.rb b/spec/system/admin/knowledge_base/public_menu_spec.rb
index d5162aa00..047d52547 100644
--- a/spec/system/admin/knowledge_base/public_menu_spec.rb
+++ b/spec/system/admin/knowledge_base/public_menu_spec.rb
@@ -64,7 +64,7 @@ RSpec.describe 'Admin Panel > Knowledge Base > Public Menu', type: :system, auth
 
   def find_locale(location, locale)
     find_location(location)
-      .find('.label', text: /#{Regexp.escape locale.system_locale.name}/i)
+      .find('.label', text: %r{#{Regexp.escape locale.system_locale.name}}i)
       .ancestor('.kb-menu-preview')
   end
 
diff --git a/spec/system/basic/richtext_spec.rb b/spec/system/basic/richtext_spec.rb
index b9d5bd2e6..f638602a9 100644
--- a/spec/system/basic/richtext_spec.rb
+++ b/spec/system/basic/richtext_spec.rb
@@ -33,7 +33,7 @@ RSpec.describe 'Richtext', type: :system do
         'and some other for browser'
       )
 
-      expect(element).to have_content(/some test for browser\s?\nand some other for browser/)
+      expect(element).to have_content(%r{some test for browser\s?\nand some other for browser})
     end
   end
 
@@ -49,7 +49,7 @@ RSpec.describe 'Richtext', type: :system do
         'and some other for browser'
       )
 
-      expect(element).to have_content(/some test for browser\s?\nand some other for browser/)
+      expect(element).to have_content(%r{some test for browser\s?\nand some other for browser})
     end
   end
 end
diff --git a/spec/system/dashboard_spec.rb b/spec/system/dashboard_spec.rb
index f076a7759..8c24aca15 100644
--- a/spec/system/dashboard_spec.rb
+++ b/spec/system/dashboard_spec.rb
@@ -6,12 +6,12 @@ RSpec.describe 'Dashboard', type: :system, authenticated_as: true do
     visit 'dashboard'
 
     expect(page).to have_css('.stat-widgets')
-    expect(page).to have_css('.ticket_waiting_time > div > div.stat-title', text: /∅ Waiting time today/i)
-    expect(page).to have_css('.ticket_escalation > div > div.stat-title', text: /Mood/i)
-    expect(page).to have_css('.ticket_channel_distribution > div > div.stat-title', text: /Channel Distribution/i)
-    expect(page).to have_css('.ticket_load_measure > div > div.stat-title', text: /Assigned/i)
-    expect(page).to have_css('.ticket_in_process > div > div.stat-title', text: /Your tickets in process/i)
-    expect(page).to have_css('.ticket_reopen > div > div.stat-title', text: /Reopening rate/i)
+    expect(page).to have_css('.ticket_waiting_time > div > div.stat-title', text: %r{∅ Waiting time today}i)
+    expect(page).to have_css('.ticket_escalation > div > div.stat-title', text: %r{Mood}i)
+    expect(page).to have_css('.ticket_channel_distribution > div > div.stat-title', text: %r{Channel Distribution}i)
+    expect(page).to have_css('.ticket_load_measure > div > div.stat-title', text: %r{Assigned}i)
+    expect(page).to have_css('.ticket_in_process > div > div.stat-title', text: %r{Your tickets in process}i)
+    expect(page).to have_css('.ticket_reopen > div > div.stat-title', text: %r{Reopening rate}i)
   end
 
   context 'when customer role is named different', authenticated_as: :authenticate do
diff --git a/spec/system/knowledge_base_public/editor_spec.rb b/spec/system/knowledge_base_public/editor_spec.rb
index 45a5cef7c..c5c7c564d 100644
--- a/spec/system/knowledge_base_public/editor_spec.rb
+++ b/spec/system/knowledge_base_public/editor_spec.rb
@@ -14,7 +14,7 @@ RSpec.describe 'Public Knowledge Base for editor', type: :system, authenticated_
 
     it 'expect to have edit button' do
       button = find '.topbar-btn'
-      expect(button['href']).to match(/edit$/)
+      expect(button['href']).to match(%r{edit$})
     end
   end
 
diff --git a/spec/system/settings/proxy_spec.rb b/spec/system/settings/proxy_spec.rb
index dff8df964..c1d0c1cdc 100644
--- a/spec/system/settings/proxy_spec.rb
+++ b/spec/system/settings/proxy_spec.rb
@@ -43,7 +43,7 @@ RSpec.describe 'Manage > Settings > System > Network', type: :system do
           click_on 'Test Connection'
 
           expect(page).to have_css('h1.modal-title', text: 'Error', wait: 5)
-          expect(page).to have_css('div.modal-body', text: /Invalid proxy address/, wait: 5)
+          expect(page).to have_css('div.modal-body', text: %r{Invalid proxy address}, wait: 5)
           expect(page).to have_button('Test Connection', visible: :visible, wait: 5)
           expect(page).to have_button('Submit', visible: :hidden, wait: 5)
 
@@ -61,7 +61,7 @@ RSpec.describe 'Manage > Settings > System > Network', type: :system do
           click_on 'Test Connection'
 
           expect(page).to have_css('h1.modal-title', text: 'Error', wait: 5)
-          expect(page).to have_css('div.modal-body', text: /Failed to open TCP connection/, wait: 5)
+          expect(page).to have_css('div.modal-body', text: %r{Failed to open TCP connection}, wait: 5)
           expect(page).to have_button('Test Connection', visible: :visible, wait: 5)
           expect(page).to have_button('Submit', visible: :hidden, wait: 5)
 
@@ -79,7 +79,7 @@ RSpec.describe 'Manage > Settings > System > Network', type: :system do
           click_on 'Test Connection'
 
           expect(page).to have_css('h1.modal-title', text: 'Error', wait: 5)
-          expect(page).to have_css('div.modal-body', text: /Access Denied/, wait: 5)
+          expect(page).to have_css('div.modal-body', text: %r{Access Denied}, wait: 5)
           expect(page).to have_button('Test Connection', visible: :visible, wait: 5)
           expect(page).to have_button('Submit', visible: :hidden, wait: 5)
 
@@ -97,7 +97,7 @@ RSpec.describe 'Manage > Settings > System > Network', type: :system do
           click_on 'Test Connection'
 
           expect(page).to have_css('h1.modal-title', text: 'Error', wait: 5)
-          expect(page).to have_css('div.modal-body', text: /Access Denied/, wait: 5)
+          expect(page).to have_css('div.modal-body', text: %r{Access Denied}, wait: 5)
           expect(page).to have_button('Test Connection', visible: :visible, wait: 5)
           expect(page).to have_button('Submit', visible: :hidden, wait: 5)
 
diff --git a/spec/system/ticket/history_spec.rb b/spec/system/ticket/history_spec.rb
index a0267555b..1c3914033 100644
--- a/spec/system/ticket/history_spec.rb
+++ b/spec/system/ticket/history_spec.rb
@@ -44,38 +44,38 @@ RSpec.describe 'Ticket history', type: :system, authenticated_as: true, time_zon
   end
 
   it "translates timestamp when attribute's tag is datetime" do
-    expect(page).to have_css('li', text: /22.01.2021 13:40/)
+    expect(page).to have_css('li', text: %r{22.01.2021 13:40})
   end
 
   it 'does not include time with UTC format' do
-    expect(page).to have_no_text(/ UTC/)
+    expect(page).to have_no_text(%r{ UTC})
   end
 
   it 'translates value when attribute is state' do
-    expect(page).to have_css('li', text: /Ticket Status von 'neu'/)
+    expect(page).to have_css('li', text: %r{Ticket Status von 'neu'})
   end
 
   it 'translates value when attribute is priority' do
-    expect(page).to have_css('li', text: /Ticket Priorität von '1 niedrig'/)
+    expect(page).to have_css('li', text: %r{Ticket Priorität von '1 niedrig'})
   end
 
   it 'translates value when attribute is internal' do
-    expect(page).to have_css('li', text: /Artikel intern von 'true'/)
+    expect(page).to have_css('li', text: %r{Artikel intern von 'true'})
   end
 
   it 'translates last_contact_at display attribute' do
-    expect(page).to have_css('li', text: /Ticket Letzter Kontakt von '22.01.2021 13:40' → '07.04.2021 00:30'/)
+    expect(page).to have_css('li', text: %r{Ticket Letzter Kontakt von '22.01.2021 13:40' → '07.04.2021 00:30'})
   end
 
   it 'translates last_contact_customer_at display attribute' do
-    expect(page).to have_css('li', text: /Ticket Letzter Kontakt \(Kunde\) von '22.01.2021 13:40' → '07.04.2021 00:30'/)
+    expect(page).to have_css('li', text: %r{Ticket Letzter Kontakt \(Kunde\) von '22.01.2021 13:40' → '07.04.2021 00:30'})
   end
 
   it 'translates last_contact_agent_at display attribute' do
-    expect(page).to have_css('li', text: /Ticket Letzter Kontakt \(Agent\) von '22.01.2021 13:40' → '07.04.2021 00:30'/)
+    expect(page).to have_css('li', text: %r{Ticket Letzter Kontakt \(Agent\) von '22.01.2021 13:40' → '07.04.2021 00:30'})
   end
 
   it 'translates pending_time display attribute' do
-    expect(page).to have_css('li', text: /Ticket Warten bis '07.04.2021 00:30'/)
+    expect(page).to have_css('li', text: %r{Ticket Warten bis '07.04.2021 00:30'})
   end
 end
diff --git a/spec/system/ticket/update/full_quote_header_spec.rb b/spec/system/ticket/update/full_quote_header_spec.rb
index 8fe7389d6..6cb4b38b3 100644
--- a/spec/system/ticket/update/full_quote_header_spec.rb
+++ b/spec/system/ticket/update/full_quote_header_spec.rb
@@ -183,9 +183,9 @@ RSpec.describe 'Ticket > Update > Full Quote Header', current_user_id: -> { curr
     def confirm_style
       case style
       when :forward
-        citation.text.match?(/Subject(.+)\nDate(.+)/)
+        citation.text.match?(%r{Subject(.+)\nDate(.+)})
       when :reply
-        citation.text.match?(/^On(.+)wrote:$/)
+        citation.text.match?(%r{^On(.+)wrote:$})
       end
     end
 
diff --git a/spec/system/user/history_spec.rb b/spec/system/user/history_spec.rb
index 4aeb90074..91319b267 100644
--- a/spec/system/user/history_spec.rb
+++ b/spec/system/user/history_spec.rb
@@ -36,18 +36,18 @@ RSpec.describe 'Ticket history', type: :system, authenticated_as: true, time_zon
   end
 
   it "translates timestamp when attribute's tag is datetime" do
-    expect(page).to have_css('li', text: /'22.01.2021 00:00'/)
+    expect(page).to have_css('li', text: %r{'22.01.2021 00:00'})
   end
 
   it 'does not include time with UTC format' do
-    expect(page).to have_no_text(/ UTC/)
+    expect(page).to have_no_text(%r{ UTC})
   end
 
   it 'translates out_of_office_start_at value to time stamp' do
-    expect(page).to have_css('li', text: /Benutzer out_of_office_start_at '22.01.2021 00:00'/)
+    expect(page).to have_css('li', text: %r{Benutzer out_of_office_start_at '22.01.2021 00:00'})
   end
 
   it 'translates out_of_office_end_at value to time stamp' do
-    expect(page).to have_css('li', text: /Benutzer out_of_office_end_at '06.04.2021 01:00'/)
+    expect(page).to have_css('li', text: %r{Benutzer out_of_office_end_at '06.04.2021 01:00'})
   end
 end
diff --git a/test/browser/agent_ticket_email_reply_keep_body_test.rb b/test/browser/agent_ticket_email_reply_keep_body_test.rb
index 92bb429e0..aa71c60bd 100644
--- a/test/browser/agent_ticket_email_reply_keep_body_test.rb
+++ b/test/browser/agent_ticket_email_reply_keep_body_test.rb
@@ -133,7 +133,7 @@ class AgentTicketEmailReplyKeepBodyTest < TestCase
 
     full_text = @browser.find_element(css: '.content.active .article-new .articleNewEdit-body').text
 
-    match = full_text.match(/\nOn (.*?) Nicole Braun wrote:/)
+    match = full_text.match(%r{\nOn (.*?) Nicole Braun wrote:})
     assert match
     assert match[1]
     assert Time.zone.parse(match[1])
@@ -157,7 +157,7 @@ class AgentTicketEmailReplyKeepBodyTest < TestCase
 
     full_text = @browser.find_element(css: '.content.active .article-new .articleNewEdit-body').text
 
-    match = full_text.match(/\nOn (.*?) Nicole Braun wrote:/)
+    match = full_text.match(%r{\nOn (.*?) Nicole Braun wrote:})
     assert_nil match
 
     # after test, turn full quote header back on again
@@ -215,7 +215,7 @@ class AgentTicketEmailReplyKeepBodyTest < TestCase
 
     full_text = @browser.find_element(css: '.content.active .article-new .articleNewEdit-body').text
 
-    match = full_text.match(/\nAm (.*?), schrieb Nicole Braun:/)
+    match = full_text.match(%r{\nAm (.*?), schrieb Nicole Braun:})
     assert match
 
     datestamp = match[1]
diff --git a/test/browser/agent_ticket_tag_test.rb b/test/browser/agent_ticket_tag_test.rb
index 88a5c8724..3f921a4e8 100644
--- a/test/browser/agent_ticket_tag_test.rb
+++ b/test/browser/agent_ticket_tag_test.rb
@@ -36,7 +36,7 @@ class AgentTicketTagTest < TestCase
       css: '.active .newTicket button.js-submit',
     )
     sleep 5
-    if !@browser.current_url.match?(/#{Regexp.quote('#ticket/zoom/')}/)
+    if !@browser.current_url.match?(%r{#{Regexp.quote('#ticket/zoom/')}})
       raise 'Unable to create ticket!'
     end
 
@@ -68,7 +68,7 @@ class AgentTicketTagTest < TestCase
     click(css: '#global-search')
     click(css: '.active .newTicket button.js-submit')
     sleep 5
-    if !@browser.current_url.match?(/#{Regexp.quote('#ticket/zoom/')}/)
+    if !@browser.current_url.match?(%r{#{Regexp.quote('#ticket/zoom/')}})
       raise 'Unable to create ticket!'
     end
 
@@ -441,7 +441,7 @@ class AgentTicketTagTest < TestCase
       css: '.active .newTicket button.js-submit',
     )
     sleep 5
-    if !@browser.current_url.match?(/#{Regexp.quote('#ticket/zoom/')}/)
+    if !@browser.current_url.match?(%r{#{Regexp.quote('#ticket/zoom/')}})
       raise 'Unable to create ticket!'
     end
 
diff --git a/test/browser/keyboard_shortcuts_test.rb b/test/browser/keyboard_shortcuts_test.rb
index 1a1088338..d2b1e609f 100644
--- a/test/browser/keyboard_shortcuts_test.rb
+++ b/test/browser/keyboard_shortcuts_test.rb
@@ -15,7 +15,7 @@ class KeyboardShortcutsTest < TestCase
     shortcut(key: 'h')
 
     # ff issue, sometimes shortcut is not fired in browser test env
-    if ENV['BROWSER'] && ENV['BROWSER'] =~ /firefox/i
+    if ENV['BROWSER'] && ENV['BROWSER'] =~ %r{firefox}i
       exists = false
       (1..4).each do |_count|
         sleep 1
diff --git a/test/browser_test_helper.rb b/test/browser_test_helper.rb
index bb80f4006..8a848e91f 100644
--- a/test/browser_test_helper.rb
+++ b/test/browser_test_helper.rb
@@ -64,7 +64,7 @@ class TestCase < ActiveSupport::TestCase
   end
 
   def browser_support_cookies
-    if browser.match?(/(internet_explorer|ie)/i)
+    if browser.match?(%r{(internet_explorer|ie)}i)
       return false
     end
 
@@ -168,7 +168,7 @@ class TestCase < ActiveSupport::TestCase
     browser_width = ENV['BROWSER_WIDTH'] || 1024
     browser_height = ENV['BROWSER_HEIGHT'] || 800
     local_browser.manage.window.resize_to(browser_width, browser_height)
-    if !ENV['REMOTE_URL']&.match?(/saucelabs|(grid|ci)\.(zammad\.org|znuny\.com)/i)
+    if !ENV['REMOTE_URL']&.match?(%r{saucelabs|(grid|ci)\.(zammad\.org|znuny\.com)}i)
       if @browsers.count == 1
         local_browser.manage.window.move_to(0, 0)
       else
@@ -420,7 +420,7 @@ class TestCase < ActiveSupport::TestCase
     instance.get(params[:url])
 
     # check if reload was successfull
-    if !instance.find_elements(css: 'body')[0] || instance.find_elements(css: 'body')[0].text =~ /unavailable or too busy/i
+    if !instance.find_elements(css: 'body')[0] || instance.find_elements(css: 'body')[0].text =~ %r{unavailable or too busy}i
       instance.navigate.refresh
     end
   end
@@ -441,7 +441,7 @@ class TestCase < ActiveSupport::TestCase
     instance = params[:browser] || @browser
     sleep 0.7
     current_url = instance.current_url
-    if !current_url.match?(/#{Regexp.quote(params[:url])}/)
+    if !current_url.match?(%r{#{Regexp.quote(params[:url])}})
       screenshot(browser: instance, comment: 'location_check_failed')
       raise "url #{current_url} is not matching #{params[:url]}"
     end
@@ -464,7 +464,7 @@ class TestCase < ActiveSupport::TestCase
     instance.navigate.refresh
 
     # check if reload was successfull
-    if !instance.find_elements(css: 'body')[0] || instance.find_elements(css: 'body')[0].text =~ /unavailable or too busy/i
+    if !instance.find_elements(css: 'body')[0] || instance.find_elements(css: 'body')[0].text =~ %r{unavailable or too busy}i
       instance.navigate.refresh
     end
     screenshot(browser: instance, comment: 'reload_after')
@@ -813,7 +813,7 @@ class TestCase < ActiveSupport::TestCase
     end
 
     # it's not working stable with ff via selenium, use js
-    if browser =~ /firefox/i && params[:css].include?('[data-name=')
+    if browser =~ %r{firefox}i && params[:css].include?('[data-name=')
       log('set_ff_trigger_workaround', params)
       instance.execute_script("$('#{params[:css]}').trigger('focusout')")
     end
@@ -1051,7 +1051,7 @@ class TestCase < ActiveSupport::TestCase
     begin
       text = if params[:attribute]
                element.attribute(params[:attribute])
-             elsif params[:css].match?(/(input|textarea)/i)
+             elsif params[:css].match?(%r{(input|textarea)}i)
                element.attribute('value')
              else
                element.text
@@ -1067,17 +1067,17 @@ class TestCase < ActiveSupport::TestCase
 
     # do cleanups (needed for richtext tests)
     if params[:cleanup]
-      text.gsub!(/\s+$/m, '')
-      params[:value].gsub!(/\s+$/m, '')
+      text.gsub!(%r{\s+$}m, '')
+      params[:value].gsub!(%r{\s+$}m, '')
     end
 
     match = false
     if params[:no_quote]
       #puts "aaaa #{text}/#{params[:value]}"
-      if text =~ /#{params[:value]}/i
+      if text =~ %r{#{params[:value]}}i
         match = $1 || true
       end
-    elsif text.match?(/#{Regexp.quote(params[:value])}/i)
+    elsif text.match?(%r{#{Regexp.quote(params[:value])}}i)
       match = true
     end
 
@@ -1204,14 +1204,14 @@ set type of task (closeTab, closeNextInOverview, stayOnTab)
     cookies = instance.manage.all_cookies
     cookies.each do |cookie|
       # :name=>"_zammad_session_c25832f4de2", :value=>"adc31cd21615cb0a7ab269184ec8b76f", :path=>"/", :domain=>"localhost", :expires=>nil, :secure=>false}
-      next if !cookie[:name].match?(/#{params[:name]}/i)
+      next if !cookie[:name].match?(%r{#{params[:name]}}i)
 
-      if params.key?(:value) && cookie[:value].to_s =~ /#{params[:value]}/i
+      if params.key?(:value) && cookie[:value].to_s =~ %r{#{params[:value]}}i
         assert(true, "matching value '#{params[:value]}' in cookie '#{cookie}'")
       else
         raise "not matching value '#{params[:value]}' in cookie '#{cookie}'"
       end
-      if params.key?(:expires) && cookie[:expires].to_s =~ /#{params[:expires]}/i
+      if params.key?(:expires) && cookie[:expires].to_s =~ %r{#{params[:expires]}}i
         assert(true, "matching expires '#{params[:expires].inspect}' in cookie '#{cookie}'")
       else
         raise "not matching expires '#{params[:expires]}' in cookie '#{cookie}'"
@@ -1244,7 +1244,7 @@ set type of task (closeTab, closeNextInOverview, stayOnTab)
     instance = params[:browser] || @browser
 
     title = instance.title
-    if title.match?(/#{params[:value]}/i)
+    if title.match?(%r{#{params[:value]}}i)
       assert(true, "matching '#{params[:value]}' in title '#{title}'")
     else
       raise "not matching '#{params[:value]}' in title '#{title}'"
@@ -1276,7 +1276,7 @@ set type of task (closeTab, closeNextInOverview, stayOnTab)
       # verify title
       if data[:title]
         title = instance.find_elements(css: '.tasks .is-active')[0].text.strip
-        if title.match?(/#{data[:title]}/i)
+        if title.match?(%r{#{data[:title]}}i)
           assert(true, "matching '#{data[:title]}' in title '#{title}'")
         else
           screenshot(browser: instance, comment: 'verify_task_failed')
@@ -1466,12 +1466,12 @@ set type of task (closeTab, closeNextInOverview, stayOnTab)
           else
             text = if params[:attribute]
                      element.attribute(params[:attribute])
-                   elsif selector.match?(/(input|textarea)/i)
+                   elsif selector.match?(%r{(input|textarea)}i)
                      element.attribute('value')
                    else
                      element.text
                    end
-            if text.match?(/#{params[:value]}/i)
+            if text.match?(%r{#{params[:value]}}i)
               assert(true, "'#{params[:value]}' found in '#{text}'")
               sleep 0.5
               return true
@@ -1534,7 +1534,7 @@ wait untill text in selector disabppears
       if params[:value]
         begin
           text = instance.find_elements(css: params[:css])[0].text
-          if !text.match?(/#{params[:value]}/i)
+          if !text.match?(%r{#{params[:value]}}i)
             assert(true, "not matching '#{params[:value]}' in text '#{text}'")
             sleep 1
             return true
@@ -1914,7 +1914,7 @@ wait untill text in selector disabppears
     11.times do
       element = instance.find_elements(css: 'body')[0]
       text = element.text
-      if text.match?(/#{Regexp.quote(data[:name])}/)
+      if text.match?(%r{#{Regexp.quote(data[:name])}})
         assert(true, 'overview created')
         overview = {
           name: name,
@@ -2028,7 +2028,7 @@ wait untill text in selector disabppears
     11.times do
       element = instance.find_elements(css: 'body')[0]
       text = element.text
-      if text.match?(/#{Regexp.quote(data[:name])}/)
+      if text.match?(%r{#{Regexp.quote(data[:name])}})
         assert(true, 'overview updated')
         overview = {
           name: name,
@@ -2296,11 +2296,11 @@ wait untill text in selector disabppears
 
     sleep 1
     9.times do
-      if instance.current_url.match?(/#{Regexp.quote('#ticket/zoom/')}/)
+      if instance.current_url.match?(%r{#{Regexp.quote('#ticket/zoom/')}})
         assert(true, 'ticket created')
         sleep 2
         id = instance.current_url
-        id.gsub!(//,)
+        id.gsub!(%r{},)
         id.gsub!(%r{^.+?/(\d+)$}, '\\1')
 
         element = instance.find_elements(css: '.content.active .ticketZoom-header .ticket-number')[0]
@@ -2541,7 +2541,7 @@ wait untill text in selector disabppears
 
         begin
           text = instance.find_elements(css: '.content.active .js-reset')[0].text
-          if text.match?(/(Discard your unsaved changes.|Verwerfen der)/)
+          if text.match?(%r{(Discard your unsaved changes.|Verwerfen der)})
             found = true
           end
         rescue
@@ -2620,7 +2620,7 @@ wait untill text in selector disabppears
 
     if data[:title]
       title = instance.find_elements(css: '.content.active .ticketZoom-header .js-objectTitle').first.text.strip
-      if title.match?(/#{data[:title]}/i)
+      if title.match?(%r{#{data[:title]}}i)
         assert(true, "matching '#{data[:title]}' in title '#{title}'")
       else
         raise "not matching '#{data[:title]}' in title '#{title}'"
@@ -2629,7 +2629,7 @@ wait untill text in selector disabppears
 
     if data[:body]
       body = instance.find_elements(css: '.content.active [data-name="body"]').first.text.strip
-      if body.match?(/#{data[:body]}/i)
+      if body.match?(%r{#{data[:body]}}i)
         assert(true, "matching '#{data[:body]}' in body '#{body}'")
       else
         raise "not matching '#{data[:body]}' in body '#{body}'"
@@ -2639,7 +2639,7 @@ wait untill text in selector disabppears
     params[:custom_data_select]&.each do |local_key, local_value|
       element = instance.find_elements(css: ".active .sidebar select[name=\"#{local_key}\"] option[selected]").first
       value = element.text.strip
-      if value.match?(/#{local_value}/i)
+      if value.match?(%r{#{local_value}}i)
         assert(true, "matching '#{value}' in #{local_key} '#{local_value}'")
       else
         raise "not matching '#{value}' in #{local_key} '#{local_value}'"
@@ -2648,7 +2648,7 @@ wait untill text in selector disabppears
     params[:custom_data_input]&.each do |local_key, local_value|
       element = instance.find_elements(css: ".active .sidebar input[name=\"#{local_key}\"]").first
       value = element.text.strip
-      if value.match?(/#{local_value}/i)
+      if value.match?(%r{#{local_value}}i)
         assert(true, "matching '#{value}' in #{local_key} '#{local_value}'")
       else
         raise "not matching '#{value}' in #{local_key} '#{local_value}'"
@@ -2766,7 +2766,7 @@ wait untill text in selector disabppears
     element.click
     sleep 1
     number = instance.find_element(css: '.content.active .ticketZoom-header .ticket-number').text
-    if !number.match?(/#{params[:number]}/)
+    if !number.match?(%r{#{params[:number]}})
       screenshot(browser: instance, comment: 'ticket_open_by_overview_open_failed_failed')
       raise "unable to open ticket #{params[:number]}!"
     end
@@ -2804,7 +2804,7 @@ wait untill text in selector disabppears
       css:     '.content.active .ticketZoom-header .ticket-number'
     )
     number = instance.find_elements(css: '.content.active .ticketZoom-header .ticket-number')[0].text
-    if !number.match?(/#{params[:number]}/)
+    if !number.match?(%r{#{params[:number]}})
       screenshot(browser: instance, comment: 'ticket_open_by_search_failed')
       raise "unable to search/find ticket #{params[:number]}!"
     end
@@ -2838,7 +2838,7 @@ wait untill text in selector disabppears
     instance.execute_script("$(\".js-global-search-result a:contains('#{params[:title]}') .nav-tab-name\").first().click()")
     sleep 1
     title = instance.find_elements(css: '.content.active .ticketZoom-header .js-objectTitle')[0].text
-    if !title.match?(/#{params[:title]}/)
+    if !title.match?(%r{#{params[:title]}})
       screenshot(browser: instance, comment: 'ticket_open_by_title_failed')
       raise "unable to search/find ticket #{params[:title]}!"
     end
@@ -2934,7 +2934,7 @@ wait untill text in selector disabppears
       css:     '.content.active h1'
     )
     name = instance.find_elements(css: '.content.active h1')[0].text
-    if !name.match?(/#{params[:value]}/)
+    if !name.match?(%r{#{params[:value]}})
       screenshot(browser: instance, comment: 'organization_open_by_search_failed')
       raise "unable to search/find org #{params[:value]}!"
     end
@@ -2970,7 +2970,7 @@ wait untill text in selector disabppears
       css:     '.content.active h1'
     )
     name = instance.find_elements(css: '.content.active h1')[0].text
-    if !name.match?(/#{params[:value]}/)
+    if !name.match?(%r{#{params[:value]}})
       screenshot(browser: instance, comment: 'user_open_by_search_failed')
       raise "unable to search/find user #{params[:value]}!"
     end
@@ -3397,7 +3397,7 @@ wait untill text in selector disabppears
     7.times do
       element = instance.find_elements(css: 'body')[0]
       text = element.text
-      if text.match?(/#{Regexp.quote(data[:name])}/)
+      if text.match?(%r{#{Regexp.quote(data[:name])}})
         assert(true, 'calendar created')
         sleep 1
         return true
@@ -3460,7 +3460,7 @@ wait untill text in selector disabppears
     7.times do
       element = instance.find_elements(css: 'body')[0]
       text = element.text
-      if text.match?(/#{Regexp.quote(data[:name])}/)
+      if text.match?(%r{#{Regexp.quote(data[:name])}})
         assert(true, 'sla created')
         sleep 1
         return true
@@ -3527,7 +3527,7 @@ wait untill text in selector disabppears
     7.times do
       element = instance.find_elements(css: 'body')[0]
       text = element.text
-      if text.match?(/#{Regexp.quote(data[:name])}/)
+      if text.match?(%r{#{Regexp.quote(data[:name])}})
         assert(true, 'text module created')
         sleep 1
         return true
@@ -3594,7 +3594,7 @@ wait untill text in selector disabppears
     11.times do
       element = instance.find_elements(css: 'body')[0]
       text = element.text
-      if text.match?(/#{Regexp.quote(data[:name])}/)
+      if text.match?(%r{#{Regexp.quote(data[:name])}})
         assert(true, 'signature created')
         sleep 1
         return true
@@ -3663,7 +3663,7 @@ wait untill text in selector disabppears
 
     element = instance.find_elements(css: 'body')[0]
     text = element.text
-    if text.match?(/#{Regexp.quote(data[:name])}/)
+    if text.match?(%r{#{Regexp.quote(data[:name])}})
       assert(true, 'group created')
       modal_disappear(browser: instance) # wait until modal has gone
 
@@ -3867,7 +3867,7 @@ wait untill text in selector disabppears
 
     element = instance.find_elements(css: 'body')[0]
     text = element.text
-    if text.match?(/#{Regexp.quote(data[:name])}/)
+    if text.match?(%r{#{Regexp.quote(data[:name])}})
       assert(true, 'role created')
       modal_disappear(browser: instance) # wait until modal has gone
 
@@ -3990,7 +3990,7 @@ wait untill text in selector disabppears
 
     element = instance.find_elements(css: 'body')[0]
     text = element.text
-    if text.match?(/#{Regexp.quote(data[:name])}/)
+    if text.match?(%r{#{Regexp.quote(data[:name])}})
       assert(true, 'role created')
       modal_disappear(browser: instance) # wait until modal has gone
 
@@ -4456,9 +4456,9 @@ wait untill text in selector disabppears
 
   def quote(string)
     string_quoted = string
-    string_quoted.gsub!(/&/, '&amp;')
-    string_quoted.gsub!(/</, '&lt;')
-    string_quoted.gsub!(/>/, '&gt;')
+    string_quoted.gsub!(%r{&}, '&amp;')
+    string_quoted.gsub!(%r{<}, '&lt;')
+    string_quoted.gsub!(%r{>}, '&gt;')
     string_quoted
   end
 
@@ -4477,7 +4477,7 @@ wait untill text in selector disabppears
       if instance
         logs = instance.manage.logs.get(:browser)
         logs.each do |log|
-          next if log.level == 'WARNING' && log.message =~ /Declaration\sdropped./ # ignore ff css warnings
+          next if log.level == 'WARNING' && log.message =~ %r{Declaration\sdropped.} # ignore ff css warnings
 
           time = Time.zone.parse(Time.zone.at(log.timestamp / 1000).to_datetime.to_s)
           puts "#{time}/#{log.level}: #{log.message}"
@@ -4818,7 +4818,7 @@ wait untill text in selector disabppears
     11.times do
       element = instance.find_elements(css: 'body')[0]
       text = element.text
-      if text.match?(/#{Regexp.quote(data[:name])}/)
+      if text.match?(%r{#{Regexp.quote(data[:name])}})
         assert(true, 'object manager attribute updated')
         sleep 1
         return true
diff --git a/test/integration/email_helper_test.rb b/test/integration/email_helper_test.rb
index 9493c2ac6..dde583e14 100644
--- a/test/integration/email_helper_test.rb
+++ b/test/integration/email_helper_test.rb
@@ -194,7 +194,7 @@ class EmailHelperTest < ActiveSupport::TestCase
       }
     )
     assert_equal('invalid', result[:result])
-    assert_match(/Host not reachable|No route to host/, result[:message_human])
+    assert_match(%r{Host not reachable|No route to host}, result[:message_human])
     assert_equal('172.42.42.42', result[:settings][:options][:host])
 
     # gmail
@@ -209,7 +209,7 @@ class EmailHelperTest < ActiveSupport::TestCase
       }
     )
     assert_equal('invalid', result[:result])
-    assert_match(/Authentication failed, username incorrect|Authentication failed, invalid credentials/, result[:message_human])
+    assert_match(%r{Authentication failed, username incorrect|Authentication failed, invalid credentials}, result[:message_human])
     assert_equal('imap.gmail.com', result[:settings][:options][:host])
 
     result = EmailHelper::Probe.inbound(
@@ -226,9 +226,9 @@ class EmailHelperTest < ActiveSupport::TestCase
 
     # if we have to many failed logins, we need to handle another error message
     if result[:message_human].present?
-      assert_match(/Authentication failed, username incorrect|Authentication failed, invalid credentials/, result[:message_human])
+      assert_match(%r{Authentication failed, username incorrect|Authentication failed, invalid credentials}, result[:message_human])
     else
-      assert_match(/Web login required/, result[:message])
+      assert_match(%r{Web login required}, result[:message])
     end
     assert_equal('imap.gmail.com', result[:settings][:options][:host])
 
@@ -338,7 +338,7 @@ class EmailHelperTest < ActiveSupport::TestCase
       'some@example.com',
     )
     assert_equal('invalid', result[:result])
-    assert_match(/Host not reachable|No route to host/, result[:message_human])
+    assert_match(%r{Host not reachable|No route to host}, result[:message_human])
     assert_equal('172.42.42.42', result[:settings][:options][:host])
 
     # gmail
@@ -378,7 +378,7 @@ class EmailHelperTest < ActiveSupport::TestCase
     if result[:message_human].present?
       assert_equal('Authentication failed!', result[:message_human])
     else
-      assert_match(/Please log in with your web browser and then try again/, result[:message])
+      assert_match(%r{Please log in with your web browser and then try again}, result[:message])
     end
     assert_equal('smtp.gmail.com', result[:settings][:options][:host])
 
diff --git a/test/integration/email_keep_on_server_test.rb b/test/integration/email_keep_on_server_test.rb
index b37504dd5..dfa002e9c 100644
--- a/test/integration/email_keep_on_server_test.rb
+++ b/test/integration/email_keep_on_server_test.rb
@@ -75,7 +75,7 @@ To: shugo@example.com
 Message-ID: <some1@example_keep_on_server>
 
 hello world
-".gsub(/\n/, "\r\n"), [], Time.zone.now)
+".gsub(%r{\n}, "\r\n"), [], Time.zone.now)
 
     # verify if message is still on server
     message_ids = imap.sort(['DATE'], ['ALL'], 'US-ASCII')
@@ -112,7 +112,7 @@ To: shugo@example.com
 Message-ID: <some2@example_keep_on_server>
 
 hello world
-".gsub(/\n/, "\r\n"), [], Time.zone.now)
+".gsub(%r{\n}, "\r\n"), [], Time.zone.now)
 
     message_meta = imap.fetch(1, ['FLAGS'])[0].attr
     assert(message_meta['FLAGS'].include?(:Seen))
@@ -163,7 +163,7 @@ To: shugo@example.com
 Message-ID: <some1@example_remove_from_server>
 
 hello world
-".gsub(/\n/, "\r\n"), [], Time.zone.now)
+".gsub(%r{\n}, "\r\n"), [], Time.zone.now)
 
     # verify if message is still on server
     message_ids = imap.sort(['DATE'], ['ALL'], 'US-ASCII')
@@ -188,7 +188,7 @@ To: shugo@example.com
 Message-ID: <some2@example_remove_from_server>
 
 hello world
-".gsub(/\n/, "\r\n"), [], Time.zone.now)
+".gsub(%r{\n}, "\r\n"), [], Time.zone.now)
 
     # verify if message is still on server
     message_ids = imap.sort(['DATE'], ['ALL'], 'US-ASCII')
@@ -213,7 +213,7 @@ To: shugo@example.com
 Message-ID: <some2@example_remove_from_server>
 
 hello world
-".gsub(/\n/, "\r\n"), [], Time.zone.now)
+".gsub(%r{\n}, "\r\n"), [], Time.zone.now)
 
     # verify if message is still on server
     message_ids = imap.sort(['DATE'], ['ALL'], 'US-ASCII')
diff --git a/test/integration/email_postmaster_to_sender.rb b/test/integration/email_postmaster_to_sender.rb
index d95644ee6..c18a9e3a1 100644
--- a/test/integration/email_postmaster_to_sender.rb
+++ b/test/integration/email_postmaster_to_sender.rb
@@ -90,7 +90,7 @@ To: shugo@example.com
 Message-ID: <#{@test_id}@zammad.test.com>
 
 Oversized Email Message Body #{'#' * 120_000}
-".gsub(/\n/, "\r\n")
+".gsub(%r{\n}, "\r\n")
 
     large_message_md5 = Digest::MD5.hexdigest(large_message)
     large_message_size = format('%<MB>.2f', MB: large_message.size.to_f / 1024 / 1024)
@@ -103,7 +103,7 @@ Oversized Email Message Body #{'#' * 120_000}
     # /tmp/oversized_mail/yyyy-mm-ddThh:mm:ss-:md5.eml
     path = Rails.root.join('tmp/oversized_mail')
     target_files = Dir.entries(path).select do |filename|
-      filename =~ /^#{large_message_md5}\.eml$/
+      filename =~ %r{^#{large_message_md5}\.eml$}
     end
     assert(target_files.present?, 'Large message .eml log file must be present.')
 
@@ -182,7 +182,7 @@ To: shugo@example.com
 Message-ID: <#{@test_id}@zammad.test.com>
 
 Oversized Email Message Body #{'#' * 120_000}
-".gsub(/\n/, "\r\n")
+".gsub(%r{\n}, "\r\n")
 
     imap.append(@folder, large_message, [], Time.zone.now)
 
@@ -192,7 +192,7 @@ Oversized Email Message Body #{'#' * 120_000}
     # /tmp/oversized_mail/yyyy-mm-ddThh:mm:ss-:md5.eml
     path = Rails.root.join('tmp/oversized_mail')
     target_files = Dir.entries(path).select do |filename|
-      filename =~ /^.+?\.eml$/
+      filename =~ %r{^.+?\.eml$}
     end
     assert_not(target_files.blank?, 'Large message .eml log file must be blank.')
 
diff --git a/test/integration/otrs_import_test.rb b/test/integration/otrs_import_test.rb
index 56c23acdf..3887c5f1b 100644
--- a/test/integration/otrs_import_test.rb
+++ b/test/integration/otrs_import_test.rb
@@ -22,7 +22,7 @@ class OtrsImportTest < ActiveSupport::TestCase
     if ENV['IMPORT_OTRS_ENDPOINT'] =~ %r{^(http|https)://((.+?)\..+?)/}
       http      = $1
       system_id = $3
-      system_id.gsub!(/[A-z]/, '') # strip chars
+      system_id.gsub!(%r{[A-z]}, '') # strip chars
     end
     assert_equal( system_id, Setting.get('system_id'), 'system_id' )
     assert_equal( http, Setting.get('http_type'), 'http_type' )
diff --git a/test/integration/slack_test.rb b/test/integration/slack_test.rb
index 21188912a..43f03f4b8 100644
--- a/test/integration/slack_test.rb
+++ b/test/integration/slack_test.rb
@@ -302,7 +302,7 @@ class SlackTest < ActiveSupport::TestCase
     channel_history['messages'].each do |message|
       next if !message['text']
 
-      if message['text'].match?(/#{search_for}/i)
+      if message['text'].match?(%r{#{search_for}}i)
         message_count += 1
         p "SUCCESS: message with #{search_for} found #{message_count} time(s)!"
       end
diff --git a/test/integration/user_agent_test.rb b/test/integration/user_agent_test.rb
index 7f36c1a06..d5dd364d1 100644
--- a/test/integration/user_agent_test.rb
+++ b/test/integration/user_agent_test.rb
@@ -27,7 +27,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"123"'))
     assert(result.body.include?('"content_type_requested":null'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # get / 404
@@ -54,7 +54,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"some value"'))
     assert(result.body.include?('"application/x-www-form-urlencoded"'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # post / 404
@@ -84,7 +84,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"some value"'))
     assert(result.body.include?('"application/x-www-form-urlencoded"'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # put / 404
@@ -110,7 +110,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"delete"'))
     assert(result.body.include?('"content_type_requested":null'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # delete / 404
@@ -141,7 +141,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"123"'))
     assert(result.body.include?('"content_type_requested":null'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # get / 401
@@ -177,7 +177,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"some value"'))
     assert(result.body.include?('"application/x-www-form-urlencoded"'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # post / 401
@@ -215,7 +215,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"some value"'))
     assert(result.body.include?('"application/x-www-form-urlencoded"'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # put / 401
@@ -250,7 +250,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"delete"'))
     assert(result.body.include?('"content_type_requested":null'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # delete / 401
@@ -283,7 +283,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"abc"'))
     assert(result.body.include?('"content_type_requested":null'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # get / 301
@@ -302,7 +302,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"abc"'))
     assert(result.body.include?('"content_type_requested":null'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # get / 401
@@ -334,7 +334,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"123"'))
     assert(result.body.include?('"content_type_requested":null'))
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # ftp / 200
@@ -346,7 +346,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert_equal(true, result.success?)
     assert_equal('200', result.code)
     assert_equal(String, result.body.class)
-    assert(result.body =~ /instructions/i)
+    assert(result.body =~ %r{instructions}i)
 
     # ftp / 401
     result = UserAgent.request(
@@ -477,7 +477,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"application/json"'))
     assert_equal('some value ', result.data['submitted']['key'])
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
 
     # get / 404
@@ -514,7 +514,7 @@ class UserAgentTest < ActiveSupport::TestCase
     assert(result.body.include?('"application/json"'))
     assert_equal('some value ', result.data['submitted']['key'])
     if ENV['ZAMMAD_PROXY_TEST'] == 'true' && ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']
-      assert_match(/"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"/, result.body)
+      assert_match(%r{"remote_ip":"#{ENV['ZAMMAD_PROXY_REMOTE_IP_CHECK']}"}, result.body)
     end
   end
 
diff --git a/test/support/searchindex_helper.rb b/test/support/searchindex_helper.rb
index 57afe0750..0af3be66d 100644
--- a/test/support/searchindex_helper.rb
+++ b/test/support/searchindex_helper.rb
@@ -39,7 +39,7 @@ prepares elasticsearch
 
     if ENV['ES_INDEX_RAND'].present?
       rand_id          = ENV.fetch('CI_JOB_ID', "r#{rand(999)}")
-      test_method_name = method_name.gsub(/[^\w]/, '_')
+      test_method_name = method_name.gsub(%r{[^\w]}, '_')
       ENV['ES_INDEX']  = "es_index_#{test_method_name.downcase}_#{rand_id}_#{rand(999_999_999)}"
     end
     if ENV['ES_INDEX'].blank?
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 286c92d48..ce0f44991 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -66,8 +66,8 @@ class ActiveSupport::TestCase
     count = 0
     lines.reverse_each do |line|
       break if line.include?('++++NEW++++TEST++++')
-      next if !line.match?(/Send notification \(#{type}\)/)
-      next if !line.match?(/to:\s#{recipient}/)
+      next if !line.match?(%r{Send notification \(#{type}\)})
+      next if !line.match?(%r{to:\s#{recipient}})
 
       count += 1
     end
diff --git a/test/unit/email_build_test.rb b/test/unit/email_build_test.rb
index f527584d3..0d7426ad1 100644
--- a/test/unit/email_build_test.rb
+++ b/test/unit/email_build_test.rb
@@ -7,7 +7,7 @@ class EmailBuildTest < ActiveSupport::TestCase
     result = Channel::EmailBuild.html_complete_check(html)
 
     assert(result.start_with?('<!DOCTYPE'), 'test 1')
-    assert(result !~ /^.+?<!DOCTYPE/, 'test 1')
+    assert(result !~ %r{^.+?<!DOCTYPE}, 'test 1')
     assert(result.include?('<html>'), 'test 1')
     assert(result.include?('font-family'), 'test 1')
     assert(result.include?('<b>test</b>'), 'test 1')
@@ -15,10 +15,10 @@ class EmailBuildTest < ActiveSupport::TestCase
     html   = 'invalid <!DOCTYPE html><html><b>test</b></html>'
     result = Channel::EmailBuild.html_complete_check(html)
 
-    assert(result !~ /^<!DOCTYPE/, 'test 2')
-    assert(result =~ /^.+?<!DOCTYPE/, 'test 2')
+    assert(result !~ %r{^<!DOCTYPE}, 'test 2')
+    assert(result =~ %r{^.+?<!DOCTYPE}, 'test 2')
     assert(result.include?('<html>'), 'test 2')
-    assert(result !~ /font-family/, 'test 2')
+    assert(result !~ %r{font-family}, 'test 2')
     assert(result.include?('<b>test</b>'), 'test 2')
 
     # Issue #1230, missing backslashes
@@ -396,6 +396,6 @@ text
     File.write('append_test.eml', mail.to_s)
 
     # Email Content should appear before the Text Content within the raw email
-    assert_match(/Email Content[\s\S]*Text Content/, mail.to_s)
+    assert_match(%r{Email Content[\s\S]*Text Content}, mail.to_s)
   end
 end
diff --git a/test/unit/email_process_auto_response_test.rb b/test/unit/email_process_auto_response_test.rb
index edd0374e4..b9662f7f3 100644
--- a/test/unit/email_process_auto_response_test.rb
+++ b/test/unit/email_process_auto_response_test.rb
@@ -238,9 +238,9 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -264,9 +264,9 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -296,14 +296,14 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
     article_auto_reply = article_p.ticket.articles[2]
-    assert_match(/Thanks for your inquiry/, article_auto_reply.subject)
-    assert_match(/me@example.com/, article_auto_reply.to)
+    assert_match(%r{Thanks for your inquiry}, article_auto_reply.subject)
+    assert_match(%r{me@example.com}, article_auto_reply.to)
     assert_equal('System', article_auto_reply.sender.name)
     assert_equal('email', article_auto_reply.type.name)
 
@@ -326,14 +326,14 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
     article_auto_reply = article_p.ticket.articles[2]
-    assert_match(/Thanks for your inquiry/, article_auto_reply.subject)
-    assert_match(/me@example.com/, article_auto_reply.to)
+    assert_match(%r{Thanks for your inquiry}, article_auto_reply.subject)
+    assert_match(%r{me@example.com}, article_auto_reply.to)
     assert_equal('System', article_auto_reply.sender.name)
     assert_equal('email', article_auto_reply.type.name)
 
@@ -575,9 +575,9 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -601,9 +601,9 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -633,14 +633,14 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_auto_reply = article_p.ticket.articles[1]
-    assert_match(/Thanks for your inquiry/, article_auto_reply.subject)
-    assert_match(/me@example.com/, article_auto_reply.to)
+    assert_match(%r{Thanks for your inquiry}, article_auto_reply.subject)
+    assert_match(%r{me@example.com}, article_auto_reply.to)
     assert_equal('System', article_auto_reply.sender.name)
     assert_equal('email', article_auto_reply.type.name)
     article_notification = article_p.ticket.articles[2]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -663,14 +663,14 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_auto_reply = article_p.ticket.articles[1]
-    assert_match(/Thanks for your inquiry/, article_auto_reply.subject)
-    assert_match(/me@example.com/, article_auto_reply.to)
+    assert_match(%r{Thanks for your inquiry}, article_auto_reply.subject)
+    assert_match(%r{me@example.com}, article_auto_reply.to)
     assert_equal('System', article_auto_reply.sender.name)
     assert_equal('email', article_auto_reply.type.name)
     article_notification = article_p.ticket.articles[2]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -781,9 +781,9 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -807,9 +807,9 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -838,9 +838,9 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
 
@@ -863,14 +863,14 @@ Some Text"
     assert_equal('Customer', article_customer.sender.name)
     assert_equal('email', article_customer.type.name)
     article_notification = article_p.ticket.articles[1]
-    assert_match(/New Ticket add. info/, article_notification.subject)
-    assert_no_match(/me@example.com/, article_notification.to)
-    assert_match(/#{agent1.email}/, article_notification.to)
+    assert_match(%r{New Ticket add. info}, article_notification.subject)
+    assert_no_match(%r{me@example.com}, article_notification.to)
+    assert_match(%r{#{agent1.email}}, article_notification.to)
     assert_equal('System', article_notification.sender.name)
     assert_equal('email', article_notification.type.name)
     article_auto_reply = article_p.ticket.articles[2]
-    assert_match(/Thanks for your inquiry/, article_auto_reply.subject)
-    assert_match(/me@example.com/, article_auto_reply.to)
+    assert_match(%r{Thanks for your inquiry}, article_auto_reply.subject)
+    assert_match(%r{me@example.com}, article_auto_reply.to)
     assert_equal('System', article_auto_reply.sender.name)
     assert_equal('email', article_auto_reply.type.name)
 
diff --git a/test/unit/ticket_notification_test.rb b/test/unit/ticket_notification_test.rb
index 9b3c1b030..9de4e2557 100644
--- a/test/unit/ticket_notification_test.rb
+++ b/test/unit/ticket_notification_test.rb
@@ -1171,15 +1171,15 @@ class TicketNotificationTest < ActiveSupport::TestCase
         changes:   human_changes,
       },
     )
-    assert_match(/Bobs's resumé/, result[:subject])
-    assert_match(/Priority/, result[:body])
-    assert_match(/1 low/, result[:body])
-    assert_match(/2 normal/, result[:body])
-    assert_match(/Pending till/, result[:body])
+    assert_match(%r{Bobs's resumé}, result[:subject])
+    assert_match(%r{Priority}, result[:body])
+    assert_match(%r{1 low}, result[:body])
+    assert_match(%r{2 normal}, result[:body])
+    assert_match(%r{Pending till}, result[:body])
     assert_match('01/11/2015 19:33 (America/St_Lucia)', result[:body])
-    assert_match(/update/, result[:body])
-    assert_no_match(/pending_till/, result[:body])
-    assert_no_match(/i18n/, result[:body])
+    assert_match(%r{update}, result[:body])
+    assert_no_match(%r{pending_till}, result[:body])
+    assert_no_match(%r{i18n}, result[:body])
 
     human_changes = bg.human_changes(@agent1, ticket1)
     assert(human_changes['Priority'], 'Check if attributes translated based on ObjectManager::Attribute')
@@ -1205,15 +1205,15 @@ class TicketNotificationTest < ActiveSupport::TestCase
       },
     )
 
-    assert_match(/Bobs's resumé/, result[:subject])
-    assert_match(/Priorität/, result[:body])
-    assert_match(/1 niedrig/, result[:body])
-    assert_match(/2 normal/, result[:body])
-    assert_match(/Warten/, result[:body])
+    assert_match(%r{Bobs's resumé}, result[:subject])
+    assert_match(%r{Priorität}, result[:body])
+    assert_match(%r{1 niedrig}, result[:body])
+    assert_match(%r{2 normal}, result[:body])
+    assert_match(%r{Warten}, result[:body])
     assert_match('12.01.2015 00:33 (Europe/Berlin)', result[:body])
-    assert_match(/aktualis/, result[:body])
-    assert_no_match(/pending_till/, result[:body])
-    assert_no_match(/i18n/, result[:body])
+    assert_match(%r{aktualis}, result[:body])
+    assert_no_match(%r{pending_till}, result[:body])
+    assert_no_match(%r{i18n}, result[:body])
 
     bg = Transaction::Notification.new(
       ticket_id:  ticket1.id,
@@ -1251,16 +1251,16 @@ class TicketNotificationTest < ActiveSupport::TestCase
       }
     )
 
-    assert_match(/Bobs's resumé/, result[:subject])
-    assert_match(/Titel/, result[:body])
-    assert_no_match(/Title/, result[:body])
-    assert_match(/some notification template test old 1/, result[:body])
-    assert_match(/some notification template test 1 #2/, result[:body])
-    assert_match(/Priorität/, result[:body])
-    assert_no_match(/Priority/, result[:body])
-    assert_match(/3 hoch/, result[:body])
-    assert_match(/2 normal/, result[:body])
-    assert_match(/aktualisier/, result[:body])
+    assert_match(%r{Bobs's resumé}, result[:subject])
+    assert_match(%r{Titel}, result[:body])
+    assert_no_match(%r{Title}, result[:body])
+    assert_match(%r{some notification template test old 1}, result[:body])
+    assert_match(%r{some notification template test 1 #2}, result[:body])
+    assert_match(%r{Priorität}, result[:body])
+    assert_no_match(%r{Priority}, result[:body])
+    assert_match(%r{3 hoch}, result[:body])
+    assert_match(%r{2 normal}, result[:body])
+    assert_match(%r{aktualisier}, result[:body])
 
     human_changes = bg.human_changes(@agent2, ticket1)
 
@@ -1277,18 +1277,18 @@ class TicketNotificationTest < ActiveSupport::TestCase
       }
     )
 
-    assert_match(/Bobs's resumé/, result[:subject])
-    assert_match(/Title/, result[:body])
-    assert_match(/some notification template test old 1/, result[:body])
-    assert_match(/some notification template test 1 #2/, result[:body])
-    assert_match(/Priority/, result[:body])
-    assert_match(/3 high/, result[:body])
-    assert_match(/2 normal/, result[:body])
-    assert_no_match(/Pending till/, result[:body])
-    assert_no_match(/2015-01-11 23:33:47 UTC/, result[:body])
-    assert_match(/update/, result[:body])
-    assert_no_match(/pending_till/, result[:body])
-    assert_no_match(/i18n/, result[:body])
+    assert_match(%r{Bobs's resumé}, result[:subject])
+    assert_match(%r{Title}, result[:body])
+    assert_match(%r{some notification template test old 1}, result[:body])
+    assert_match(%r{some notification template test 1 #2}, result[:body])
+    assert_match(%r{Priority}, result[:body])
+    assert_match(%r{3 high}, result[:body])
+    assert_match(%r{2 normal}, result[:body])
+    assert_no_match(%r{Pending till}, result[:body])
+    assert_no_match(%r{2015-01-11 23:33:47 UTC}, result[:body])
+    assert_match(%r{update}, result[:body])
+    assert_no_match(%r{pending_till}, result[:body])
+    assert_no_match(%r{i18n}, result[:body])
 
     # en notification
     ticket1.escalation_at = Time.zone.parse('2019-04-01T10:00:00Z')
diff --git a/test/unit/ticket_trigger_recursive_disabled_test.rb b/test/unit/ticket_trigger_recursive_disabled_test.rb
index ecca70964..945c56acc 100644
--- a/test/unit/ticket_trigger_recursive_disabled_test.rb
+++ b/test/unit/ticket_trigger_recursive_disabled_test.rb
@@ -4282,7 +4282,7 @@ class TicketTriggerRecursiveDisabledTest < ActiveSupport::TestCase
     assert_match('Zammad <zammad@localhost>', article1.from)
     assert_match('smith@example.com', article1.to)
     assert_match('Thanks for your inquiry (aaäöüßad asd)!', article1.subject)
-    assert_match(/.+cid:.+?@zammad.example.com.+/, article1.body)
+    assert_match(%r{.+cid:.+?@zammad.example.com.+}, article1.body)
     assert_equal(1, article1.attachments.count)
     assert_equal('789', article1.attachments[0].size)
     assert_equal('text/html', article1.content_type)
diff --git a/test/unit/ticket_trigger_test.rb b/test/unit/ticket_trigger_test.rb
index 434a314b9..d61c65f83 100644
--- a/test/unit/ticket_trigger_test.rb
+++ b/test/unit/ticket_trigger_test.rb
@@ -4308,7 +4308,7 @@ class TicketTriggerTest < ActiveSupport::TestCase
     assert_match('Zammad <zammad@localhost>', article1.from)
     assert_match('smith@example.com', article1.to)
     assert_match('Thanks for your inquiry (aaäöüßad asd)!', article1.subject)
-    assert_match(/.+cid:.+?@zammad.example.com.+/, article1.body)
+    assert_match(%r{.+cid:.+?@zammad.example.com.+}, article1.body)
     assert_equal(1, article1.attachments.count)
     assert_equal('789', article1.attachments[0].size)
     assert_equal('text/html', article1.content_type)