Get it from the LogJam page.
What's changed? Well, let me go look through 300 lines of ChangeLogs, and even those have gaps... this branch has been in development for half a year.
But we've also been busy with other things, so maybe it isn't so much.
- Challenge-response authentication support
- LogJam no longer sends your password in a replayable format. (Only available on sites that support it: livejournal.com is one of them.)
- New layout of widgets reduces clutter
- Those of you who've been around for a while will recognize it as the way LogJam used to work years ago. :)
- Better offline support
- Logging in is now optional, sync is faster, and the entry browser is better.
- Better command-line support
- You can sync, post, and even cat/grep entries stored offline from the command-line.
- Much-improved backend design
- Including optionally building without the GUI (! useful when combined with the above commands), building on Windows, and we'll even soon support posting, editing, etc. entries on sites using the Blogger protocol.
- Tray icon
- Optional tray icon hides/shows main window, even when you're not using checkfriends—by popular request.
(It's been so long since I used the 4.2 branch I don't know what else is new. If you spot anything, let me know and I'll add it to the announcement.)