I'm happy to announce that RT 4.0.11, the latest stable release, is now available.
This release of RT contains two large updates.
The WYSIWYG editor (CKEditor) used on ticket creation and reply pages has been updated to address numerous reports of breakages when using IE 10. It also includes fixes for many other browsers. You can read more about the included changes. We are shipping 18.104.22.168, upgraded from 3.4.1.
If you use RT with mod_perl and have not updated from SetHandler perl-script to SetHandler modperl, RT will now refuse to start. You can read more about mod_perl configuration here.
A complete changelog is available