5.3.0 is in beta right now and getting ready for final release. There are a huge number of fixes and cleanup. There are also a few nice new features as well. A great release over all. Here is a breakdown of some of the highlights. For the full version see http://wiki.cerb5.com/wiki/5.3.0
Two new plug-ins were added.
Call Logging - It is like those well you were out pad then something designed to link into tickets although I am sure over time it will be easier to link into tickets. Right now you have to manually create the link.
Feed Reader - It allows you to read feeds from diff source. Example are forum, blogs, wiki's, etc. It is a nice way to manage resources to keep an eye on stuff posted and stuff that moderation on it.
Choosers get a face lift. They now allow you to pull stuff by typing not just using a mouse. A great improvement in that feature.*
Knowledge Base and Comments get attachments. That is a long time request that several people will be happy about.
Snippets get custom fields. That will make them much easier to deal with.