diff --git a/.rubocop.yml b/.rubocop.yml
index 36ac3d1f7..3b8a84515 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -252,8 +252,6 @@ Lint/UselessAssignment:
   Enabled: false
 Lint/NonLocalExitFromIterator:
   Enabled: false
-Style/ColonMethodCall:
-  Enabled: false
 Rails/Date:
   Enabled: false
 Lint/UnreachableCode:
diff --git a/app/controllers/getting_started_controller.rb b/app/controllers/getting_started_controller.rb
index f9cffaad5..6ad348a94 100644
--- a/app/controllers/getting_started_controller.rb
+++ b/app/controllers/getting_started_controller.rb
@@ -891,7 +891,7 @@ curl http://localhost/api/v1/getting_started -v -u #{login}:#{password}
     begin
       mxs = Resolv::DNS.open do |dns|
         ress = dns.getresources(domain, Resolv::DNS::Resource::IN::MX)
-        ress.map { |r| [r.exchange.to_s, IPSocket::getaddress(r.exchange.to_s), r.preference] }
+        ress.map { |r| [r.exchange.to_s, IPSocket.getaddress(r.exchange.to_s), r.preference] }
       end
     rescue Exception => e
       logger.error e.message
diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
index 75acdd1d7..ae1eb22b1 100644
--- a/app/controllers/sessions_controller.rb
+++ b/app/controllers/sessions_controller.rb
@@ -34,13 +34,13 @@ class SessionsController < ApplicationController
     user.activity_stream_log( 'session started', user.id, true )
 
     # auto population of default collections
-    collections, assets = SessionHelper::default_collections(user)
+    collections, assets = SessionHelper.default_collections(user)
 
     # add session user assets
     assets = user.assets(assets)
 
     # get models
-    models = SessionHelper::models(user)
+    models = SessionHelper.models(user)
 
     # check logon session
     logon_session_key = nil
@@ -76,7 +76,7 @@ class SessionsController < ApplicationController
 
     # check logon session
     if params['logon_session']
-      session = SessionHelper::get( params['logon_session'] )
+      session = SessionHelper.get( params['logon_session'] )
       if session
         user_id = session.data[:user_id]
       end
@@ -84,7 +84,7 @@ class SessionsController < ApplicationController
 
     if !user_id
       # get models
-      models = SessionHelper::models()
+      models = SessionHelper.models()
 
       render json: {
         error: 'no valid session',
@@ -102,13 +102,13 @@ class SessionsController < ApplicationController
     user = User.find( user_id )
 
     # auto population of default collections
-    collections, assets = SessionHelper::default_collections(user)
+    collections, assets = SessionHelper.default_collections(user)
 
     # add session user assets
     assets = user.assets(assets)
 
     # get models
-    models = SessionHelper::models(user)
+    models = SessionHelper.models(user)
 
     # return current session
     render json: {
@@ -278,7 +278,7 @@ class SessionsController < ApplicationController
 
   def delete
     return if deny_if_not_role(Z_ROLENAME_ADMIN)
-    SessionHelper::destroy( params[:id] )
+    SessionHelper.destroy( params[:id] )
     render json: {}
   end
 
diff --git a/lib/geo_ip/zammad_geo_ip.rb b/lib/geo_ip/zammad_geo_ip.rb
index 9259ae35e..8fb1285c0 100644
--- a/lib/geo_ip/zammad_geo_ip.rb
+++ b/lib/geo_ip/zammad_geo_ip.rb
@@ -12,7 +12,7 @@ class GeoIp::ZammadGeoIp
 
     # do lookup
     host = 'https://geo.zammad.com'
-    url  = "/lookup?ip=#{CGI::escape address}"
+    url  = "/lookup?ip=#{CGI.escape address}"
     data = {}
     begin
       response = UserAgent.get(
diff --git a/lib/geo_location/gmaps.rb b/lib/geo_location/gmaps.rb
index a96b32a8e..59a61ec1a 100644
--- a/lib/geo_location/gmaps.rb
+++ b/lib/geo_location/gmaps.rb
@@ -3,7 +3,7 @@
 class GeoLocation::Gmaps
 
   def self.geocode(address)
-    url = "http://maps.googleapis.com/maps/api/geocode/json?address=#{CGI::escape address}&sensor=true"
+    url = "http://maps.googleapis.com/maps/api/geocode/json?address=#{CGI.escape address}&sensor=true"
     response = UserAgent.get(url)
     return if !response.success?
 
diff --git a/lib/import/otrs.rb b/lib/import/otrs.rb
index af8735a98..220a3f2d2 100644
--- a/lib/import/otrs.rb
+++ b/lib/import/otrs.rb
@@ -211,7 +211,7 @@ module Import::OTRS
   def self.ticket(ticket_ids)
     url = 'public.pl?Action=Export;Type=Ticket;'
     ticket_ids.each {|ticket_id|
-      url = url + "TicketID=#{CGI::escape ticket_id};"
+      url = url + "TicketID=#{CGI.escape ticket_id};"
     }
     response = request( url )
     return if !response
diff --git a/lib/sessions.rb b/lib/sessions.rb
index a40482698..2568f5a63 100644
--- a/lib/sessions.rb
+++ b/lib/sessions.rb
@@ -47,7 +47,7 @@ returns
     }
 
     # destory old session if needed
-    if File::exist?( path )
+    if File.exist?( path )
       Sessions.destory(client_id)
     end
 
@@ -82,7 +82,7 @@ returns
     path = "#{@path}/"
 
     # just make sure that spool path exists
-    if !File::exist?( path )
+    if !File.exist?( path )
       FileUtils.mkpath path
     end
 
@@ -293,7 +293,7 @@ returns
     check    = true
     count    = 0
     while check
-      if File::exist?( path + filename )
+      if File.exist?( path + filename )
         count += 1
         filename = "#{filename}-#{count}"
       else
@@ -445,7 +445,7 @@ returns
     }
     files.sort.each {|entry|
       filename = "#{path}/#{entry}"
-      next if !File::exist?( filename )
+      next if !File.exist?( filename )
       File.open( filename, 'rb' ) { |file|
         all   = file.read
         spool = JSON.parse( all )
@@ -500,7 +500,7 @@ returns
   def self.jobs
 
     # just make sure that spool path exists
-    if !File::exist?( @path )
+    if !File.exist?( @path )
       FileUtils.mkpath @path
     end