Quite a bit!
File comparisons are faster and interactivity is better while recomputing changes, and initial support was added for comparing files using synchronisation points.
Folder comparisons now have extra columns so you can see more file information when doing your comparison. There is also a new shallow comparison option, speeding things up nicely for people dealing with folders full of huge files.
Version control view has had some significant compatibility updates, culminating in the death of the dreaded ‘patch failed’ dialog, as Meld now uses more reliable ways of interacting with version control systems. Some big updates went in to support more commands, give better feedback, and do a better job of launching conflict comparisons.
Meld also received lots of little improvements here and there. We now have better themeability (a big deal for dark theme fans), support for relaunching recent comparisons, and a new UI for starting comparisons. Last but not least, Meld’s Windows support has improved, and bundled installers are becoming available for Windows users (thanks to Keegan Witt).