Improvements and patches to the Junk Mail algorithm allow it to produce the same message scores as SpamBayes (another Bayesian spam filter - so good it is often used as a benchmark). What does this mumbo-jumbo mean? It means Thunderbird is now better at classifying your email as spam (or not) correctly. Scott highly recommends anyone trying out the new junk mail filter to first clear out the training file and retrain it. For that purpose, a new button for clearing the training data has been added (bug 237151) for convenience (previously, we had to delete the training.dat file manually).
Thunderbird's new IDLE support for IMAP (bug 141369) also sees many improvements and bugfixes. Simply put, IDLE is a command that allows IMAP email servers to transmit updates to the client in real time. This saves the client from having to continuously poll the server to achieve the effect of new mail appearing immediately. All in all, an exceptionally useful command that saves Thunderbird the work of polling IMAP servers continuously.
New emoticons (bug id=237045are also included in this build, and the artwork comes from Stephen Horlander of the Pinstripe theme fame. Very nice, compared to the old ones which were terribly dated (I had emoticons turned off because I didn't like them).
The new Win32 installer is an early attempt at rolling out the Mozilla Thunderbird installer targetted for the 0.6 milestone release (as stated in the Mozilla Thunderbird roadmap). I tried it out and it was fully functional, but there are several nitty gritty issues to be sorted out.
Running the installer presents you with this screen:
A little messed up, but this is an early test build after all. Scott is mostly leveraging off the work put into Firefox's Win32 installer. You next get to choose a standard or custom install.
Selecting custom allows you to add additional extensions - at this moment, Scott has only bundled in the Offline extension. Plans are in store to bundle other extensions as well, including the DOM Inspector.
Unfortunately (at least to me), the installer silently places shortcut icons on the desktop, in the start menu, and in the quick launch bar. The installer should have asked first. (I see someone else has already whinedabout this) I think with sufficient well-founded feedback, the Thunderbird team will come around to getting that feature into the installer.