Index: app/controllers/application_controller.rb
===================================================================
--- app/controllers/application_controller.rb	(revision 19958)
+++ app/controllers/application_controller.rb	(working copy)
@@ -564,8 +564,13 @@
   end
 
   def render_feed(items, options={})
+    @type = options[:type]
     @items = (items || []).to_a
-    @items.sort! {|x,y| y.event_datetime <=> x.event_datetime }
+    if @type == :issues
+      @items.sort! {|x,y| y.updated_on <=> x.updated_on }
+    else
+      @items.sort! {|x,y| y.event_datetime <=> x.event_datetime }
+    end
     @items = @items.slice(0, Setting.feeds_limit.to_i)
     @title = options[:title] || Setting.app_title
     render :template => "common/feed", :formats => [:atom], :layout => false,
Index: app/controllers/issues_controller.rb
===================================================================
--- app/controllers/issues_controller.rb	(revision 19958)
+++ app/controllers/issues_controller.rb	(working copy)
@@ -63,7 +63,8 @@
         format.atom do
           @issues = @query.issues(:limit => Setting.feeds_limit.to_i)
           render_feed(@issues,
-                      :title => "#{@project || Setting.app_title}: #{l(:label_issue_plural)}")
+                      :title => "#{@project || Setting.app_title}: #{l(:label_issue_plural)}",
+                      :type => :issues)
         end
         format.csv do
           @issues = @query.issues(:limit => Setting.issues_export_limit.to_i)
Index: app/views/common/feed.atom.builder
===================================================================
--- app/views/common/feed.atom.builder	(revision 19958)
+++ app/views/common/feed.atom.builder	(working copy)
@@ -9,7 +9,7 @@
   xml.link    "rel" => "alternate", "href" => url_for(:params => request.query_parameters.merge(:format => nil, :key => nil), :only_path => false, :protocol => protocol, :host => host)
   xml.id      home_url
   xml.icon    favicon_url
-  xml.updated((@items.first ? @items.first.event_datetime : Time.now).xmlschema)
+  xml.updated((@items.first ? (@type == :issues ? @items.first.updated_on : @items.first.event_datetime) : Time.now).xmlschema)
   xml.author  { xml.name "#{Setting.app_title}" }
   xml.generator(:uri => Redmine::Info.url) { xml.text! Redmine::Info.app_name; }
   @items.each do |item|
@@ -22,7 +22,7 @@
       end
       xml.link "rel" => "alternate", "href" => url
       xml.id url
-      xml.updated item.event_datetime.xmlschema
+      xml.updated (@type == :issues ? item.updated_on : item.event_datetime).xmlschema
       author = item.event_author if item.respond_to?(:event_author)
       xml.author do
         xml.name(author)