--- app/models/mailer.rb.orig	2016-07-27 13:48:08.000000000 -0400
+++ app/models/mailer.rb	2016-07-27 14:20:04.000000000 -0400
@@ -43,6 +43,7 @@
   def issue_add(issue, to_users, cc_users)
     redmine_headers 'Project' => issue.project.identifier,
                     'Issue-Id' => issue.id,
+                    'Issue-Tracker' => issue.tracker.name,
                     'Issue-Author' => issue.author.login
     redmine_headers 'Issue-Assignee' => issue.assigned_to.login if issue.assigned_to
     message_id issue
@@ -53,7 +54,7 @@
     @issue_url = url_for(:controller => 'issues', :action => 'show', :id => issue)
     mail :to => to_users,
       :cc => cc_users,
-      :subject => "[#{issue.project.name} - #{issue.tracker.name} ##{issue.id}] (#{issue.status.name}) #{issue.subject}"
+      :subject => "[#{issue.project.name} - ##{issue.id}] #{issue.subject}"
   end
 
   # Notifies users about a new issue
@@ -70,14 +71,12 @@
     issue = journal.journalized
     redmine_headers 'Project' => issue.project.identifier,
                     'Issue-Id' => issue.id,
+                    'Issue-Tracker' => issue.tracker.name,
                     'Issue-Author' => issue.author.login
     redmine_headers 'Issue-Assignee' => issue.assigned_to.login if issue.assigned_to
     message_id journal
     references issue
     @author = journal.user
-    s = "[#{issue.project.name} - #{issue.tracker.name} ##{issue.id}] "
-    s << "(#{issue.status.name}) " if journal.new_value_for('status_id')
-    s << issue.subject
     @issue = issue
     @users = to_users + cc_users
     @journal = journal
@@ -85,7 +84,7 @@
     @issue_url = url_for(:controller => 'issues', :action => 'show', :id => issue, :anchor => "change-#{journal.id}")
     mail :to => to_users,
       :cc => cc_users,
-      :subject => s
+      :subject => "[#{issue.project.name} - ##{issue.id}] #{issue.subject}"
   end
 
   # Notifies users about an issue update
@@ -429,6 +428,7 @@
     end
     if @references_objects
       headers[:references] = @references_objects.collect {|o| "<#{self.class.references_for(o)}>"}.join(' ')
+      headers[:in_reply_to] = @references_objects.collect {|o| "<#{self.class.references_for(o)}>"}.join(' ')
     end
 
     m = if block_given?