diff --git a/.gitlab/ci/integration/es.yml b/.gitlab/ci/integration/es.yml
index 6317dd090..80b73d9b8 100644
--- a/.gitlab/ci/integration/es.yml
+++ b/.gitlab/ci/integration/es.yml
@@ -13,20 +13,26 @@
     - bundle exec rspec --tag searchindex --tag ~type:system
     - bundle exec rails test test/integration/report_test.rb
 
-es:5.6:
-  <<: *template_integration_es
-  variables:
-    ELASTICSEARCH_TAG: '5.6'
-    RAILS_ENV: "test"
-
 es:6:
   <<: *template_integration_es
   variables:
     ELASTICSEARCH_TAG: '6'
     RAILS_ENV: "test"
 
+es:6.5:
+  <<: *template_integration_es
+  variables:
+    ELASTICSEARCH_TAG: '6.5'
+    RAILS_ENV: "test"
+
 es:7:
   <<: *template_integration_es
   variables:
     ELASTICSEARCH_TAG: '7'
     RAILS_ENV: "test"
+
+es:7.0:
+  <<: *template_integration_es
+  variables:
+    ELASTICSEARCH_TAG: '7.0'
+    RAILS_ENV: "test"
diff --git a/.rubocop/todo.yml b/.rubocop/todo.yml
index b4afbc8ea..6d96503cb 100644
--- a/.rubocop/todo.yml
+++ b/.rubocop/todo.yml
@@ -733,6 +733,7 @@ Metrics/PerceivedComplexity:
     - 'app/models/application_model/checks_attribute_values_and_length.rb'
     - 'app/models/application_model/checks_user_columns_fillup.rb'
     - 'app/models/application_model/has_attachments.rb'
+    - 'app/models/application_model/can_lookup_search_index_attributes.rb'
     - 'app/models/authorization.rb'
     - 'app/models/avatar.rb'
     - 'app/models/calendar.rb'
diff --git a/app/models/application_model/can_lookup_search_index_attributes.rb b/app/models/application_model/can_lookup_search_index_attributes.rb
index 6d57ffbc5..68937b4be 100644
--- a/app/models/application_model/can_lookup_search_index_attributes.rb
+++ b/app/models/application_model/can_lookup_search_index_attributes.rb
@@ -4,10 +4,13 @@ module ApplicationModel::CanLookupSearchIndexAttributes
 
 =begin
 
-lookup name of ref. objects
+This function return the attributes for the elastic search with relation hash values.
+
+It can be run with parameter include_references: false to skip the relational hashes to prevent endless loops.
 
   ticket = Ticket.find(3)
   attributes = ticket.search_index_attribute_lookup
+  attributes = ticket.search_index_attribute_lookup(include_references: false)
 
 returns
 
@@ -15,10 +18,11 @@ returns
 
 =end
 
-  def search_index_attribute_lookup
-
+  def search_index_attribute_lookup(include_references: true)
     attributes = self.attributes
     self.attributes.each do |key, value|
+      break if !include_references
+
       attribute_name = key.to_s
 
       # ignore standard attribute if needed
@@ -74,34 +78,7 @@ returns
     relation_model = relation_class.lookup(id: attributes[attribute_name])
     return if !relation_model
 
-    relation_model.search_index_value
-  end
-
-=begin
-
-This function returns the relational search value.
-
-  organization = Organization.find(1)
-  value = organization.search_index_value
-
-returns
-
-  value = {"name"=>"Zammad Foundation"}
-
-=end
-
-  def search_index_value
-
-    # get name of ref object
-    value = nil
-    if respond_to?('name')
-      value = send('name')
-    elsif respond_to?('search_index_data')
-      value = send('search_index_data')
-      return if value == true
-    end
-
-    value
+    relation_model.search_index_attribute_lookup(include_references: false)
   end
 
 =begin
diff --git a/app/models/chat/session/search_index.rb b/app/models/chat/session/search_index.rb
index a76f977ae..ec1fbaefc 100644
--- a/app/models/chat/session/search_index.rb
+++ b/app/models/chat/session/search_index.rb
@@ -15,7 +15,7 @@ returns
 
 =end
 
-  def search_index_attribute_lookup
+  def search_index_attribute_lookup(include_references: true)
     attributes = super
     return if !attributes
 
diff --git a/app/models/concerns/has_search_index_backend.rb b/app/models/concerns/has_search_index_backend.rb
index b6b9a4e1b..626279dd5 100644
--- a/app/models/concerns/has_search_index_backend.rb
+++ b/app/models/concerns/has_search_index_backend.rb
@@ -92,7 +92,7 @@ returns
     # start background job to transfer data to search index
     return true if !SearchIndexBackend.enabled?
 
-    new_search_index_value = search_index_value
+    new_search_index_value = search_index_attribute_lookup(include_references: false)
     return if new_search_index_value.blank?
 
     Models.indexable.each do |local_object|
@@ -174,36 +174,6 @@ returns
     true
   end
 
-=begin
-
-get data to store in search index
-
-  ticket = Ticket.find(123)
-  result = ticket.search_index_data
-
-returns
-
-  result = {
-    attribute1: 'some value',
-    attribute2: ['value 1', 'value 2'],
-    ...
-  }
-
-=end
-
-  def search_index_data
-    attributes = {}
-    %w[name note].each do |key|
-      next if !self[key]
-      next if self[key].respond_to?('blank?') && self[key].blank?
-
-      attributes[key] = self[key]
-    end
-    return true if attributes.blank?
-
-    attributes
-  end
-
   def ignore_search_indexing?(_action)
     false
   end
diff --git a/app/models/knowledge_base/answer/translation.rb b/app/models/knowledge_base/answer/translation.rb
index 8e96df97e..0e1dfe7c0 100644
--- a/app/models/knowledge_base/answer/translation.rb
+++ b/app/models/knowledge_base/answer/translation.rb
@@ -51,7 +51,7 @@ class KnowledgeBase::Answer::Translation < ApplicationModel
     [answer_id, title.parameterize].join('-')
   end
 
-  def search_index_attribute_lookup
+  def search_index_attribute_lookup(include_references: true)
     attrs = super
 
     attrs['title']      = ActionController::Base.helpers.strip_tags attrs['title']
diff --git a/app/models/knowledge_base/answer/translation/content.rb b/app/models/knowledge_base/answer/translation/content.rb
index b2d925e97..e0ca0bb1e 100644
--- a/app/models/knowledge_base/answer/translation/content.rb
+++ b/app/models/knowledge_base/answer/translation/content.rb
@@ -39,7 +39,7 @@ class KnowledgeBase::Answer::Translation::Content < ApplicationModel
     attributes
   end
 
-  def search_index_attribute_lookup
+  def search_index_attribute_lookup(include_references: true)
     attrs = super
     attrs['body'] = ActionController::Base.helpers.strip_tags attrs['body']
     attrs
diff --git a/app/models/knowledge_base/category/translation.rb b/app/models/knowledge_base/category/translation.rb
index d6022c75d..ca2f8394b 100644
--- a/app/models/knowledge_base/category/translation.rb
+++ b/app/models/knowledge_base/category/translation.rb
@@ -29,7 +29,7 @@ class KnowledgeBase::Category::Translation < ApplicationModel
     category.assets(data)
   end
 
-  def search_index_attribute_lookup
+  def search_index_attribute_lookup(include_references: true)
     attrs = super
 
     attrs['title']    = ActionController::Base.helpers.strip_tags attrs['title']
diff --git a/app/models/knowledge_base/translation.rb b/app/models/knowledge_base/translation.rb
index 938448af3..b29a99963 100644
--- a/app/models/knowledge_base/translation.rb
+++ b/app/models/knowledge_base/translation.rb
@@ -19,7 +19,7 @@ class KnowledgeBase::Translation < ApplicationModel
     knowledge_base.assets(data)
   end
 
-  def search_index_attribute_lookup
+  def search_index_attribute_lookup(include_references: true)
     attrs = super
 
     attrs['title'] = ActionController::Base.helpers.strip_tags attrs['title']
diff --git a/app/models/organization.rb b/app/models/organization.rb
index 2b83c7efa..9ac1ce3a8 100644
--- a/app/models/organization.rb
+++ b/app/models/organization.rb
@@ -17,6 +17,8 @@ class Organization < ApplicationModel
 
   has_many :members, class_name: 'User'
   has_many :tickets, class_name: 'Ticket'
+  belongs_to :created_by,  class_name: 'User'
+  belongs_to :updated_by,  class_name: 'User'
 
   before_create :domain_cleanup
   before_update :domain_cleanup
@@ -25,7 +27,7 @@ class Organization < ApplicationModel
   validates :name,   presence: true
   validates :domain, presence: { message: 'required when Domain Based Assignment is enabled' }, if: :domain_assignment
 
-  association_attributes_ignored :tickets
+  association_attributes_ignored :tickets, :created_by, :updated_by
 
   activity_stream_permission 'admin.role'
 
diff --git a/app/models/organization/search_index.rb b/app/models/organization/search_index.rb
index 139b1b43b..1b373c930 100644
--- a/app/models/organization/search_index.rb
+++ b/app/models/organization/search_index.rb
@@ -4,27 +4,17 @@ class Organization
   module SearchIndex
     extend ActiveSupport::Concern
 
-=begin
-
-lookup name of ref. objects
-
-  organization = Organization.find(123)
-  attributes = organization.search_index_attribute_lookup
-
-returns
-
-  attributes # object with lookup data
-
-=end
-
-    def search_index_attribute_lookup
+    def search_index_attribute_lookup(include_references: true)
       attributes = super
 
-      # add org members for search index data
-      attributes['members'] = []
-      users = User.where(organization_id: id)
-      users.each do |user|
-        attributes['members'].push user.search_index_data
+      if include_references
+
+        # add org members for search index data
+        attributes['members'] = []
+        users = User.where(organization_id: id)
+        users.each do |user|
+          attributes['members'].push user.search_index_attribute_lookup(include_references: false)
+        end
       end
 
       attributes
diff --git a/app/models/stats_store.rb b/app/models/stats_store.rb
index 7f3fbcf17..a30ea0209 100644
--- a/app/models/stats_store.rb
+++ b/app/models/stats_store.rb
@@ -2,7 +2,6 @@
 
 class StatsStore < ApplicationModel
   include HasSearchIndexBackend
-  include StatsStore::SearchIndex
 
   belongs_to :stats_storable, polymorphic: true
 
diff --git a/app/models/stats_store/search_index.rb b/app/models/stats_store/search_index.rb
deleted file mode 100644
index 386fdadfc..000000000
--- a/app/models/stats_store/search_index.rb
+++ /dev/null
@@ -1,20 +0,0 @@
-# Copyright (C) 2012-2016 Zammad Foundation, http://zammad-foundation.org/
-module StatsStore::SearchIndex
-
-  def search_index_attribute_lookup
-    attributes = super
-    return if !attributes
-
-    begin
-      record = attributes['stats_store_object'].constantize.lookup(id: o_id)
-      return if !record
-
-      attributes['stats_store_object_ref'] = record.search_index_attribute_lookup
-    rescue
-      return
-    end
-
-    attributes
-  end
-
-end
diff --git a/app/models/ticket/search_index.rb b/app/models/ticket/search_index.rb
index e8217bf1c..96cc4ad78 100644
--- a/app/models/ticket/search_index.rb
+++ b/app/models/ticket/search_index.rb
@@ -2,20 +2,7 @@
 module Ticket::SearchIndex
   extend ActiveSupport::Concern
 
-=begin
-
-lookup name of ref. objects
-
-  ticket = Ticket.find(123)
-  result = ticket.search_index_attribute_lookup
-
-returns
-
-  attributes # object with lookup data
-
-=end
-
-  def search_index_attribute_lookup
+  def search_index_attribute_lookup(include_references: true)
     attributes = super
     return if !attributes
 
@@ -40,7 +27,7 @@ returns
     articles.each do |article|
 
       # lookup attributes of ref. objects (normally name and note)
-      article_attributes = article.search_index_attribute_lookup
+      article_attributes = article.search_index_attribute_lookup(include_references: false)
 
       # remove note needed attributes
       ignore = %w[message_id_md5 ticket]
diff --git a/app/models/user/search_index.rb b/app/models/user/search_index.rb
index 26b1c87a6..c91c87a60 100644
--- a/app/models/user/search_index.rb
+++ b/app/models/user/search_index.rb
@@ -4,68 +4,19 @@ class User
   module SearchIndex
     extend ActiveSupport::Concern
 
-=begin
-
-lookup name of ref. objects
-
-  user = User.find(123)
-  attributes = user.search_index_attribute_lookup
-
-returns
-
-  attributes # object with lookup data
-
-=end
-
-    def search_index_attribute_lookup
+    def search_index_attribute_lookup(include_references: true)
       attributes = super
+      attributes.delete('password')
 
-      attributes['permissions'] = []
-      permissions_with_child_ids.each do |permission_id|
-        permission = ::Permission.lookup(id: permission_id)
-        next if !permission
+      if include_references
+        attributes['permissions'] = []
+        permissions_with_child_ids.each do |permission_id|
+          permission = ::Permission.lookup(id: permission_id)
+          next if !permission
 
-        attributes['permissions'].push permission.name
-      end
-      attributes['role_ids'] = role_ids
-
-      attributes
-    end
-
-=begin
-
-get data to store in search index
-
-  user = User.find(2)
-  result = user.search_index_data
-
-returns
-
-  result = {
-    attribute1: 'some value',
-    attribute2: ['value 1', 'value 2'],
-    ...
-  }
-
-=end
-
-    def search_index_data
-      attributes = {}
-      self.attributes.each do |key, value|
-        next if key == 'password'
-        next if !value
-        next if value.respond_to?('blank?') && value.blank?
-
-        attributes[key] = value
-      end
-      return if attributes.blank?
-
-      if attributes['organization_id'].present?
-        organization = Organization.lookup(id: attributes['organization_id'])
-        if organization
-          attributes['organization'] = organization.name
-          attributes['organization_ref'] = organization.search_index_data
+          attributes['permissions'].push permission.name
         end
+        attributes['role_ids'] = role_ids
       end
 
       attributes
diff --git a/db/migrate/20201013095141_elastic_search_lower65_obsolete.rb b/db/migrate/20201013095141_elastic_search_lower65_obsolete.rb
new file mode 100644
index 000000000..3ef8f97df
--- /dev/null
+++ b/db/migrate/20201013095141_elastic_search_lower65_obsolete.rb
@@ -0,0 +1,9 @@
+class ElasticSearchLower65Obsolete < ActiveRecord::Migration[5.2]
+  def change
+
+    # return if it's a new setup
+    return if !Setting.exists?(name: 'system_init_done')
+
+    Setting.find_by(name: 'es_multi_index').destroy
+  end
+end
diff --git a/db/seeds/settings.rb b/db/seeds/settings.rb
index 2fa159eee..a89e8f63b 100644
--- a/db/seeds/settings.rb
+++ b/db/seeds/settings.rb
@@ -2980,15 +2980,6 @@ Setting.create_if_not_exists(
   preferences: { online_service_disable: true },
   frontend:    false
 )
-Setting.create_if_not_exists(
-  title:       'Elasticsearch Multi Index',
-  name:        'es_multi_index',
-  area:        'SearchIndex::Elasticsearch',
-  description: 'Define if Elasticsearch is using multiple indexes.',
-  state:       false,
-  preferences: { online_service_disable: true },
-  frontend:    false
-)
 
 Setting.create_if_not_exists(
   title:       'Import Mode',
diff --git a/lib/report/ticket_generic_time.rb b/lib/report/ticket_generic_time.rb
index e508f00a8..a12fb9e12 100644
--- a/lib/report/ticket_generic_time.rb
+++ b/lib/report/ticket_generic_time.rb
@@ -33,7 +33,7 @@ returns
     }
 
     without_merged_tickets = {
-      'state' => {
+      'state.name' => {
         'operator' => 'is not',
         'value'    => 'merged'
       }
@@ -156,7 +156,7 @@ returns
     end
 
     without_merged_tickets = {
-      'state' => {
+      'state.name' => {
         'operator' => 'is not',
         'value'    => 'merged'
       }
diff --git a/lib/search_index_backend.rb b/lib/search_index_backend.rb
index ae5bc233c..252e79297 100644
--- a/lib/search_index_backend.rb
+++ b/lib/search_index_backend.rb
@@ -479,9 +479,9 @@ example for aggregations within one year
       current_user_id = current_user.id
     end
 
-    query_must = []
+    query_must     = []
     query_must_not = []
-    relative_map = {
+    relative_map   = {
       day:    'd',
       year:   'y',
       month:  'M',
@@ -490,7 +490,13 @@ example for aggregations within one year
     }
     if selector.present?
       selector.each do |key, data|
-        key_tmp = key.sub(/^.+?\./, '')
+        data = data.clone
+        table, key_tmp = key.split(/\./)
+        if key_tmp.blank?
+          key_tmp = table
+          table   = 'ticket'
+        end
+
         wildcard_or_term = 'term'
         if data['value'].is_a?(Array)
           wildcard_or_term = 'terms'
@@ -539,22 +545,27 @@ example for aggregations within one year
 
         # use .keyword and wildcard search in cases where query contains non A-z chars
         if data['operator'] == 'contains' || data['operator'] == 'contains not'
+
           if data['value'].is_a?(Array)
             data['value'].each_with_index do |value, index|
-              next if !value.is_a?(String) || value !~ /[A-z]/ || value !~ /\W/
+              next if !value.is_a?(String) || value !~ /[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']) && data['value'] =~ /\W/
+          elsif data['value'].is_a?(String) && /[A-z]/.match?(data['value'])
             data['value'] = "*#{data['value']}*"
             key_tmp += '.keyword'
             wildcard_or_term = 'wildcard'
           end
         end
 
+        if table != 'ticket'
+          key_tmp = "#{table}.#{key_tmp}"
+        end
+
         # is/is not/contains/contains not
         case data['operator']
         when 'is', 'is not', 'contains', 'contains not'
@@ -702,29 +713,12 @@ return true if backend is configured
   def self.build_index_name(index = nil)
     local_index = "#{Setting.get('es_index')}_#{Rails.env}"
     return local_index if index.blank?
-    return "#{local_index}/#{index}" if lower_equal_es56?
 
     "#{local_index}_#{index.underscore.tr('/', '_')}"
   end
 
 =begin
 
-return true if the elastic search version is lower equal 5.6
-
-  result = SearchIndexBackend.lower_equal_es56?
-
-returns
-
-  result = true
-
-=end
-
-  def self.lower_equal_es56?
-    Setting.get('es_multi_index') == false
-  end
-
-=begin
-
 generate url for index or document access (only for internal use)
 
   # url to access single document in index (in case with_pipeline or not)
@@ -770,7 +764,7 @@ generate url for index or document access (only for internal use)
     url = "#{url}/#{index}"
 
     # add document type
-    if with_document_type && !lower_equal_es56?
+    if with_document_type
       url = "#{url}/_doc"
     end
 
@@ -801,7 +795,7 @@ generate url for index or document access (only for internal use)
     message = if response&.error&.match?('Connection refused')
                 "Elasticsearch is not reachable, probably because it's not running or even installed."
               elsif url.end_with?('pipeline/zammad-attachment', 'pipeline=zammad-attachment') && response.code == 400
-                'The installed attachment plugin could not handle the request payload. Ensure that the correct attachment plugin is installed (5.6 => ingest-attachment, 2.4 - 5.5 => mapper-attachments).'
+                'The installed attachment plugin could not handle the request payload. Ensure that the correct attachment plugin is installed (ingest-attachment).'
               else
                 'Check the response and payload for detailed information: '
               end
diff --git a/lib/tasks/search_index_es.rake b/lib/tasks/search_index_es.rake
index 9c56fd4e1..0118c78d6 100644
--- a/lib/tasks/search_index_es.rake
+++ b/lib/tasks/search_index_es.rake
@@ -6,18 +6,13 @@ namespace :searchindex do
     print 'drop indexes...'
 
     # drop indexes
-    if es_multi_index?
-      Models.indexable.each do |local_object|
-        SearchIndexBackend.index(
-          action: 'delete',
-          name:   local_object.name,
-        )
-      end
-    else
+    Models.indexable.each do |local_object|
       SearchIndexBackend.index(
         action: 'delete',
+        name:   local_object.name,
       )
     end
+
     puts 'done'
 
     Rake::Task['searchindex:drop_pipeline'].execute
@@ -26,37 +21,17 @@ namespace :searchindex do
   task :create, [:opts] => %i[environment searchindex:configured searchindex:version_supported] do |_t, _args|
     print 'create indexes...'
 
-    if es_multi_index?
-      Setting.set('es_multi_index', true)
-    else
-      Setting.set('es_multi_index', false)
-    end
-
     settings = {
       'index.mapping.total_fields.limit': 2000,
     }
 
     # create indexes
-    if es_multi_index?
-      Models.indexable.each do |local_object|
-        SearchIndexBackend.index(
-          action: 'create',
-          name:   local_object.name,
-          data:   {
-            mappings: get_mapping_properties_object(local_object),
-            settings: settings,
-          }
-        )
-      end
-    else
-      mapping = {}
-      Models.indexable.each do |local_object|
-        mapping.merge!(get_mapping_properties_object(local_object))
-      end
+    Models.indexable.each do |local_object|
       SearchIndexBackend.index(
         action: 'create',
+        name:   local_object.name,
         data:   {
-          mappings: mapping,
+          mappings: get_mapping_properties_object(local_object),
           settings: settings,
         }
       )
@@ -68,10 +43,6 @@ namespace :searchindex do
   end
 
   task :create_pipeline, [:opts] => %i[environment searchindex:configured searchindex:version_supported] do |_t, _args|
-    if !es_pipeline?
-      Setting.set('es_pipeline', '')
-      next
-    end
 
     # update processors
     pipeline = Setting.get('es_pipeline')
@@ -80,17 +51,11 @@ namespace :searchindex do
       Setting.set('es_pipeline', pipeline)
     end
 
-    # define pipeline_field_attributes
-    # ES 5.6 and nower has no ignore_missing support
     pipeline_field_attributes = {
       ignore_failure: true,
+      ignore_missing: true,
     }
-    if es_multi_index?
-      pipeline_field_attributes = {
-        ignore_failure: true,
-        ignore_missing: true,
-      }
-    end
+
     print 'create pipeline (pipeline)... '
     SearchIndexBackend.processors(
       "_ingest/pipeline/#{pipeline}": [
@@ -136,7 +101,6 @@ namespace :searchindex do
   end
 
   task :drop_pipeline, [:opts] => %i[environment searchindex:configured searchindex:version_supported] do |_t, _args|
-    next if !es_pipeline?
 
     # update processors
     pipeline = Setting.get('es_pipeline')
@@ -181,7 +145,7 @@ namespace :searchindex do
   task :version_supported, [:opts] => :environment do |_t, _args|
     next if es_version_supported?
 
-    abort "Your Elasticsearch version is not supported! Please update your version to a greater equal than 5.6.0 (Your current version: #{es_version})."
+    abort "Your Elasticsearch version is not supported! Please update your version to a greater equal than 6.5.0 (Your current version: #{es_version})."
   end
 
   task :configured, [:opts] => :environment do |_t, _args|
@@ -214,10 +178,7 @@ mapping = {
 
 def get_mapping_properties_object(object)
 
-  name = object.name
-  if es_multi_index?
-    name = '_doc'
-  end
+  name = '_doc'
   result = {
     name => {
       properties: {}
@@ -231,13 +192,6 @@ def get_mapping_properties_object(object)
   string_raw  = { 'type': 'keyword', 'ignore_above': 5012 }
   boolean_raw = { 'type': 'boolean' }
 
-  # for elasticsearch 5.6 and lower
-  if !es_multi_index?
-    string_type = 'string'
-    string_raw  = { 'type': 'string', 'index': 'not_analyzed' }
-    boolean_raw = { 'type': 'boolean', 'index': 'not_analyzed' }
-  end
-
   object.columns_hash.each do |key, value|
     if value.type == :string && value.limit && value.limit <= 5000 && store_columns.exclude?(key)
       result[name][:properties][key] = {
@@ -276,46 +230,19 @@ def get_mapping_properties_object(object)
     end
   end
 
-  # es with mapper-attachments plugin
-  if object.name == 'Ticket'
-
-    # do not server attachments if document is requested
+  case object.name
+  when 'Ticket'
     result[name][:_source] = {
       excludes: ['article.attachment']
     }
-
-    # for elasticsearch 5.5 and lower
-    if !es_pipeline?
-      result[name][:_source] = {
-        excludes: ['article.attachment']
-      }
-      result[name][:properties][:article] = {
-        type:              'nested',
-        include_in_parent: true,
-        properties:        {
-          attachment: {
-            type: 'attachment',
-          }
-        }
-      }
-    end
-  end
-
-  if object.name == 'KnowledgeBase::Answer::Translation'
-    # do not server attachments if document is requested
+    result[name][:properties][:article] = {
+      type:              'nested',
+      include_in_parent: true,
+    }
+  when 'KnowledgeBase::Answer::Translation'
     result[name][:_source] = {
       excludes: ['attachment']
     }
-
-    # for elasticsearch 5.5 and lower
-    if !es_pipeline?
-      result[name][:_source] = {
-        excludes: ['attachment']
-      }
-      result[name][:properties][:attachment] = {
-        type: 'attachment',
-      }
-    end
   end
 
   return result if es_type_in_mapping?
@@ -335,40 +262,25 @@ def es_version
   end
 end
 
+def es_version_int
+  number = es_version
+  return 0 if !number
+
+  number_split = es_version.split('.')
+  "#{number_split[0]}#{format('%<minor>03d', minor: number_split[1])}#{format('%<patch>03d', patch: number_split[2])}".to_i
+end
+
 def es_version_supported?
-  version_split = es_version.split('.')
-  version       = "#{version_split[0]}#{format('%<minor>03d', minor: version_split[1])}#{format('%<patch>03d', patch: version_split[2])}".to_i
 
-  # only versions greater/equal than 5.6.0 are supported
-  return if version < 5_006_000
-
-  true
-end
-
-# no es_pipeline for elasticsearch 5.5 and lower
-def es_pipeline?
-  number = es_version
-  return false if number.blank?
-  return false if number.match?(/^[2-4]\./)
-  return false if number.match?(/^5\.[0-5]\./)
-
-  true
-end
-
-# no multi index for elasticsearch 5.6 and lower
-def es_multi_index?
-  number = es_version
-  return false if number.blank?
-  return false if number.match?(/^[2-5]\./)
+  # only versions greater/equal than 6.5.0 are supported
+  return if es_version_int < 6_005_000
 
   true
 end
 
 # no type in mapping
 def es_type_in_mapping?
-  number = es_version
-  return true if number.blank?
-  return true if number.match?(/^[2-6]\./)
+  return true if es_version_int < 7_000_000
 
   false
 end
diff --git a/spec/lib/search_index_backend_spec.rb b/spec/lib/search_index_backend_spec.rb
index 30ac440c2..7058cbeae 100644
--- a/spec/lib/search_index_backend_spec.rb
+++ b/spec/lib/search_index_backend_spec.rb
@@ -164,17 +164,32 @@ RSpec.describe SearchIndexBackend, searchindex: true do
 
   describe '.selectors' do
 
-    let(:organization1) { create :organization }
-    let(:agent1) { create :agent, organization: organization1 }
-    let(:customer1) { create :customer, organization: organization1 }
-    let(:ticket1) { create :ticket, title: 'some-title1', state_id: 1, created_by: agent1 }
-    let(:ticket2) { create :ticket, title: 'some_title2', state_id: 4 }
-    let(:ticket3) { create :ticket, title: 'some::title3', state_id: 1 }
+    let(:group1) { create :group }
+    let(:organization1) { create :organization, note: 'hihi' }
+    let(:agent1) { create :agent, organization: organization1, groups: [group1] }
+    let(:customer1) { create :customer, organization: organization1, firstname: 'special-first-name' }
+    let(:ticket1) do
+      ticket = create :ticket, title: 'some-title1', state_id: 1, created_by: agent1
+      ticket.tag_add('t1', 1)
+      ticket
+    end
+    let(:ticket2) do
+      ticket = create :ticket, title: 'some_title2', state_id: 4
+      ticket.tag_add('t2', 1)
+      ticket
+    end
+    let(:ticket3) do
+      ticket = create :ticket, title: 'some::title3', state_id: 1
+      ticket.tag_add('t1', 1)
+      ticket.tag_add('t2', 1)
+      ticket
+    end
     let(:ticket4) { create :ticket, title: 'phrase some-title4', state_id: 1 }
     let(:ticket5) { create :ticket, title: 'phrase some_title5', state_id: 1 }
     let(:ticket6) { create :ticket, title: 'phrase some::title6', state_id: 1 }
     let(:ticket7) { create :ticket, title: 'some title7', state_id: 1 }
-    let(:ticket8) { create :ticket, title: 'sometitle', state_id: 1, owner: agent1, customer: customer1 }
+    let(:ticket8) { create :ticket, title: 'sometitle', group: group1, state_id: 1, owner: agent1, customer: customer1, organization: organization1 }
+    let(:article8) { create :ticket_article, ticket: ticket8, subject: 'lorem ipsum' }
 
     before do
       Ticket.destroy_all # needed to remove not created tickets
@@ -192,11 +207,96 @@ RSpec.describe SearchIndexBackend, searchindex: true do
       travel 1.second
       ticket7.search_index_update_backend
       travel 1.second
-      ticket8.search_index_update_backend
+      article8.ticket.search_index_update_backend
       described_class.refresh
     end
 
     context 'query with contains' do
+      it 'finds records with tags which contains all' do
+        result = described_class.selectors('Ticket',
+                                           { 'ticket.tags'=>{ 'operator' => 'contains all', 'value' => 't1, t2' } },
+                                           {},
+                                           {
+                                             field: 'created_at', # sort to verify result
+                                           })
+        expect(result).to eq({ count: 1, ticket_ids: [ticket3.id.to_s] })
+      end
+
+      it 'finds records with tags which contains one' do
+        result = described_class.selectors('Ticket',
+                                           { 'ticket.tags'=>{ 'operator' => 'contains one', 'value' => 't1, t2' } },
+                                           {},
+                                           {
+                                             field: 'created_at', # sort to verify result
+                                           })
+        expect(result).to eq({ count: 3, ticket_ids: [ticket3.id.to_s, ticket2.id.to_s, ticket1.id.to_s] })
+      end
+
+      it 'finds records with tags which contains all not' do
+        result = described_class.selectors('Ticket',
+                                           { 'ticket.tags'=>{ 'operator' => 'contains all not', 'value' => 't2' } },
+                                           {},
+                                           {
+                                             field: 'created_at', # sort to verify result
+                                           })
+        expect(result).to eq({ count: 6, ticket_ids: [ticket8.id.to_s, ticket7.id.to_s, ticket6.id.to_s, ticket5.id.to_s, ticket4.id.to_s, ticket1.id.to_s] })
+      end
+
+      it 'finds records with tags which contains one not' do
+        result = described_class.selectors('Ticket',
+                                           { 'ticket.tags'=>{ 'operator' => 'contains one not', 'value' => 't1' } },
+                                           {},
+                                           {
+                                             field: 'created_at', # sort to verify result
+                                           })
+        expect(result).to eq({ count: 6, ticket_ids: [ticket8.id.to_s, ticket7.id.to_s, ticket6.id.to_s, ticket5.id.to_s, ticket4.id.to_s, ticket2.id.to_s] })
+      end
+
+      it 'finds records with organization note' do
+        result = described_class.selectors('Ticket',
+                                           {
+                                             'organization.note' => {
+                                               'operator' => 'contains',
+                                               'value'    => 'hihi',
+                                             },
+                                           },
+                                           {},
+                                           {
+                                             field: 'created_at', # sort to verify result
+                                           })
+        expect(result).to eq({ count: 1, ticket_ids: [ticket8.id.to_s] })
+      end
+
+      it 'finds records with customer firstname' do
+        result = described_class.selectors('Ticket',
+                                           {
+                                             'customer.firstname' => {
+                                               'operator' => 'contains',
+                                               'value'    => 'special',
+                                             },
+                                           },
+                                           {},
+                                           {
+                                             field: 'created_at', # sort to verify result
+                                           })
+        expect(result).to eq({ count: 1, ticket_ids: [ticket8.id.to_s] })
+      end
+
+      it 'finds records with article subject' do
+        result = described_class.selectors('Ticket',
+                                           {
+                                             'article.subject' => {
+                                               'operator' => 'contains',
+                                               'value'    => 'ipsum',
+                                             },
+                                           },
+                                           {},
+                                           {
+                                             field: 'created_at', # sort to verify result
+                                           })
+        expect(result).to eq({ count: 1, ticket_ids: [ticket8.id.to_s] })
+      end
+
       it 'finds records with pre_condition not_set' do
         result = described_class.selectors('Ticket',
                                            {
diff --git a/spec/models/chat/session_spec.rb b/spec/models/chat/session_spec.rb
index 0a6c7ec58..e2cc9ab2f 100644
--- a/spec/models/chat/session_spec.rb
+++ b/spec/models/chat/session_spec.rb
@@ -17,7 +17,7 @@ RSpec.describe Chat::Session, type: :model do
     end
 
     it 'verify chat attribute' do
-      expect(chat_session.search_index_attribute_lookup['chat']).to eq chat.name
+      expect(chat_session.search_index_attribute_lookup['chat']['name']).to eq chat.name
     end
 
   end
diff --git a/spec/models/user/can_lookup_search_index_attributes_examples.rb b/spec/models/user/can_lookup_search_index_attributes_examples.rb
index 9417f06fe..11dc2f014 100644
--- a/spec/models/user/can_lookup_search_index_attributes_examples.rb
+++ b/spec/models/user/can_lookup_search_index_attributes_examples.rb
@@ -5,16 +5,7 @@ RSpec.shared_examples 'CanLookupSearchIndexAttributes' do
       user         = create(:agent, organization: organization)
 
       value = user.search_index_value_by_attribute('organization_id')
-      expect(value).to eq('Tomato42')
-    end
-  end
-
-  describe '.search_index_value' do
-    it 'returns correct value' do
-      organization = create(:organization, name: 'Tomato42', note: 'special recipe')
-
-      value = organization.search_index_value
-      expect(value).to eq('Tomato42')
+      expect(value['name']).to eq('Tomato42')
     end
   end
 
diff --git a/spec/requests/search_spec.rb b/spec/requests/search_spec.rb
index 9f25eb2ad..6e029a982 100644
--- a/spec/requests/search_spec.rb
+++ b/spec/requests/search_spec.rb
@@ -363,7 +363,7 @@ RSpec.describe 'Search', type: :request, searchindex: true do
       expect(json_response['assets']['Organization'][organization_nested.id.to_s]).to be_truthy
       expect(json_response['assets']['User'][customer_nested.id.to_s]).to be_truthy
 
-      post '/api/v1/search/User', params: { query: 'organization:Tomato42' }, as: :json
+      post '/api/v1/search/User', params: { query: 'organization.name:Tomato42' }, as: :json
       expect(response).to have_http_status(:ok)
       expect(json_response).to be_a_kind_of(Hash)
       expect(json_response).to be_truthy
@@ -383,7 +383,7 @@ RSpec.describe 'Search', type: :request, searchindex: true do
       expect(json_response['assets']['Organization'][organization_nested.id.to_s]).to be_truthy
       expect(json_response['assets']['User'][customer_nested.id.to_s]).to be_truthy
 
-      post '/api/v1/search/User', params: { query: 'organization:Cucumber43' }, as: :json
+      post '/api/v1/search/User', params: { query: 'organization.name:Cucumber43' }, as: :json
       expect(response).to have_http_status(:ok)
       expect(json_response).to be_a_kind_of(Hash)
       expect(json_response).to be_truthy
@@ -400,7 +400,7 @@ RSpec.describe 'Search', type: :request, searchindex: true do
       expect(json_response['assets']['Organization'][organization_nested.id.to_s]).to be_truthy
       expect(json_response['assets']['Ticket'][ticket_nested.id.to_s]).to be_truthy
 
-      post '/api/v1/search/Ticket', params: { query: 'organization:Tomato42' }, as: :json
+      post '/api/v1/search/Ticket', params: { query: 'organization.name:Tomato42' }, as: :json
       expect(response).to have_http_status(:ok)
       expect(json_response).to be_a_kind_of(Hash)
       expect(json_response).to be_truthy
@@ -418,7 +418,7 @@ RSpec.describe 'Search', type: :request, searchindex: true do
       expect(json_response['assets']['Organization'][organization_nested.id.to_s]).to be_truthy
       expect(json_response['assets']['Ticket'][ticket_nested.id.to_s]).to be_truthy
 
-      post '/api/v1/search/Ticket', params: { query: 'organization:Cucumber43' }, as: :json
+      post '/api/v1/search/Ticket', params: { query: 'organization.name:Cucumber43' }, as: :json
       expect(response).to have_http_status(:ok)
       expect(json_response).to be_a_kind_of(Hash)
       expect(json_response).to be_truthy
diff --git a/test/integration/elasticsearch_test.rb b/test/integration/elasticsearch_test.rb
index 0511bb454..4d4cc511e 100644
--- a/test/integration/elasticsearch_test.rb
+++ b/test/integration/elasticsearch_test.rb
@@ -82,14 +82,6 @@ class ElasticsearchTest < ActiveSupport::TestCase
   test 'a - objects' do
 
     # user
-    attributes = @agent.search_index_data
-    assert_equal('E', attributes['firstname'])
-    assert_equal('S', attributes['lastname'])
-    assert_equal('es-agent@example.com', attributes['email'])
-    assert(attributes['preferences'])
-    assert_not(attributes['password'])
-    assert_not(attributes['organization'])
-
     attributes = @agent.search_index_attribute_lookup
     assert_equal('E', attributes['firstname'])
     assert_equal('S', attributes['lastname'])
@@ -104,14 +96,9 @@ class ElasticsearchTest < ActiveSupport::TestCase
     assert_equal('es-customer1@example.com', attributes['email'])
     assert(attributes['preferences'])
     assert_not(attributes['password'])
-    assert_equal('Customer Organization Update', attributes['organization'])
+    assert_equal('Customer Organization Update', attributes['organization']['name'])
 
     # organization
-    attributes = @organization1.search_index_data
-    assert_equal('Customer Organization Update', attributes['name'])
-    assert_equal('some note', attributes['note'])
-    assert_not(attributes['members'])
-
     attributes = @organization1.search_index_attribute_lookup
     assert_equal('Customer Organization Update', attributes['name'])
     assert_equal('some note', attributes['note'])
@@ -150,15 +137,15 @@ class ElasticsearchTest < ActiveSupport::TestCase
     )
 
     attributes = ticket1.search_index_attribute_lookup
-    assert_equal('Users', attributes['group'])
-    assert_equal('new', attributes['state'])
-    assert_equal('2 normal', attributes['priority'])
+    assert_equal('Users', attributes['group']['name'])
+    assert_equal('new', attributes['state']['name'])
+    assert_equal('2 normal', attributes['priority']['name'])
 
     assert_equal('ES', attributes['customer']['firstname'])
     assert_equal('Customer1', attributes['customer']['lastname'])
     assert_equal('es-customer1@example.com', attributes['customer']['email'])
     assert_not(attributes['customer']['password'])
-    assert_equal('Customer Organization Update', attributes['customer']['organization'])
+    assert_nil(attributes['customer']['organization'])
 
     assert_equal('-', attributes['owner']['login'])
     assert_equal('-', attributes['owner']['firstname'])
@@ -466,7 +453,7 @@ class ElasticsearchTest < ActiveSupport::TestCase
 
     result = Ticket.search(
       current_user: @agent,
-      query:        'state:open',
+      query:        'state.name:open',
       limit:        15,
     )
     assert(result[0], 'record 1')