diff --git a/app/models/issue.rb b/app/models/issue.rb
index 670921eb0..408ab485b 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -48,6 +48,7 @@ class Issue < ApplicationRecord
                      :scope => lambda {|options| options[:open_issues] ? self.open : self.all}
 
   acts_as_event :title => Proc.new {|o| "#{o.tracker.name} ##{o.id} (#{o.status}): #{o.subject}"},
+                :datetime => Proc.new {|o| o.updated_on},
                 :url => Proc.new {|o| {:controller => 'issues', :action => 'show', :id => o.id}},
                 :type => Proc.new {|o| 'issue' + (o.closed? ? '-closed' : '')}
 
diff --git a/test/functional/issues_controller_test.rb b/test/functional/issues_controller_test.rb
index ee477dffa..175f6bd35 100644
--- a/test/functional/issues_controller_test.rb
+++ b/test/functional/issues_controller_test.rb
@@ -1246,6 +1246,16 @@ class IssuesControllerTest < Redmine::ControllerTest
       assert_select 'link[rel=self][href=?]', 'http://test.host/projects/ecookbook/issues.atom'
       assert_select 'link[rel=alternate][href=?]', 'http://test.host/projects/ecookbook/issues'
       assert_select 'entry link[href=?]', 'http://test.host/issues/1'
+
+      assert_select 'entry' do |entries|
+        entries.each do |entry|
+          issue_id = entry.at('id').text.split('/').last.to_i
+          issue = Issue.find(issue_id)
+          formatted_updated_on = issue.updated_on.utc.iso8601
+          # <updated> element should use the value of `Issue#updated_on`
+          assert_select entry, 'updated', text: formatted_updated_on
+        end
+      end
     end
   end