That was a mistake and I have rectified it, the 4.5 announcement is now current.

That release included many fixes/enhancements made as part of the SOA platform work, as well as other features specific to 4.5.

The release notes attached to the download should contain a summary of all the changes, look here for more details.

http://www.jboss.org/file-access/default/members/jbossesb/downloads/4.5.GA/notes/release.txt