Index: app/models/mailer.rb
===================================================================
--- app/models/mailer.rb	(revision 5115)
+++ app/models/mailer.rb	(working copy)
@@ -85,7 +85,7 @@
     subject l(:mail_subject_reminder, :count => issues.size, :days => days)
     body :issues => issues,
          :days => days,
-         :issues_url => url_for(:controller => 'issues', :action => 'index', :set_filter => 1, :assigned_to_id => user.id, :sort_key => 'due_date', :sort_order => 'asc')
+         :issues_url => url_for(:controller => 'issues', :action => 'index', :set_filter => 1, :assigned_to_id => user.id, :sort => 'due_date:asc')
     render_multipart('reminder', body)
   end