diff --git a/app/models/observer/ticket/article/communicate_email/background_job.rb b/app/models/observer/ticket/article/communicate_email/background_job.rb
index 6e8feb137..049c3eacc 100644
--- a/app/models/observer/ticket/article/communicate_email/background_job.rb
+++ b/app/models/observer/ticket/article/communicate_email/background_job.rb
@@ -17,23 +17,6 @@ class Observer::Ticket::Article::CommunicateEmail::BackgroundJob
       fail "Can't send email, no channel definde for email_address id '#{ticket.group.email_address_id}'"
     end
 
-    # get references headers
-    references = []
-    if record.in_reply_to
-      references.push record.in_reply_to
-    end
-
-    # add all other article message_ids
-    Ticket::Article.where(ticket_id: record.ticket_id).each {|article|
-      if article.in_reply_to && !article.in_reply_to.empty?
-        references.push article.in_reply_to
-      end
-      next if !article.message_id
-      next if !article.message_id.empty?
-      next if article.id == @article_id
-      references.push article.message_id
-    }
-
     channel = ticket.group.email_address.channel
 
     # get linked channel and send
@@ -41,7 +24,7 @@ class Observer::Ticket::Article::CommunicateEmail::BackgroundJob
       {
         message_id: record.message_id,
         in_reply_to: record.in_reply_to,
-        references: references,
+        references: ticket.get_references([record.message_id]),
         from: record.from,
         to: record.to,
         cc: record.cc,
diff --git a/app/models/observer/ticket/notification/background_job.rb b/app/models/observer/ticket/notification/background_job.rb
index 029610c89..0180a98c1 100644
--- a/app/models/observer/ticket/notification/background_job.rb
+++ b/app/models/observer/ticket/notification/background_job.rb
@@ -164,7 +164,9 @@ class Observer::Ticket::Notification::BackgroundJob
           article: article,
           recipient: user,
           changes: changes,
-        }
+        },
+        references: ticket.get_references,
+        main_object: ticket,
       )
       Rails.logger.debug "sent ticket email notifiaction to agent (#{@p[:type]}/#{ticket.id}/#{user.email})"
     end
diff --git a/app/models/ticket.rb b/app/models/ticket.rb
index c7358446d..ce564cb20 100644
--- a/app/models/ticket.rb
+++ b/app/models/ticket.rb
@@ -531,6 +531,42 @@ condition example
     [query, bind_params, tables]
   end
 
+=begin
+
+get all email references headers of a ticket, to exclude some, parse it as array into method
+
+  references = ticket.get_references
+
+result
+
+  ['message-id-1234', 'message-id-5678']
+
+ignore references header(s)
+
+  references = ticket.get_references(['message-id-5678'])
+
+result
+
+  ['message-id-1234']
+
+=end
+
+  def get_references(ignore = [])
+    references = []
+    Ticket::Article.select('in_reply_to, message_id').where(ticket_id: id).each {|article|
+      if !article.in_reply_to.empty?
+        references.push article.in_reply_to
+      end
+      next if !article.message_id
+      next if article.message_id.empty?
+      references.push article.message_id
+    }
+    ignore.each {|item|
+      references.delete(item)
+    }
+    references
+  end
+
   private
 
   def check_generate
diff --git a/lib/notification_factory.rb b/lib/notification_factory.rb
index 8db5e1540..5293530f8 100644
--- a/lib/notification_factory.rb
+++ b/lib/notification_factory.rb
@@ -96,10 +96,11 @@ module NotificationFactory
 =begin
 
   success = NotificationFactory.send(
-    recipient:     User.find(123),
+    recipient:    User.find(123),
     subject:      'sime subject',
     body:         'some body',
     content_type: '', # optional, e. g. 'text/html'
+    references:   ['message-id123', 'message-id456'],
   )
 
 =end
@@ -121,6 +122,7 @@ module NotificationFactory
         from: sender,
         to: data[:recipient][:email],
         subject: data[:subject],
+        references: data[:references],
         body: data[:body],
         content_type: content_type,
       },
@@ -133,9 +135,11 @@ module NotificationFactory
   NotificationFactory.notification(
     template: 'password_reset',
     user: User.find(2),
-    objects:  {
+    objects: {
       recipient: User.find(2),
     },
+    main_object: ticket.find(123), # optional
+    references: ['message-id123', 'message-id456'],
   )
 
 =end
@@ -149,11 +153,17 @@ module NotificationFactory
       objects: data[:objects],
     )
 
+    # rebuild subject
+    if data[:main_object] && data[:main_object].respond_to?(:subject_build)
+      result[:subject] = data[:main_object].subject_build(result[:subject])
+    end
+
     NotificationFactory.send(
       recipient: data[:user],
       subject: result[:subject],
       body: result[:body],
       content_type: 'text/html',
+      references: data[:references],
     )
   end