A third tasty Release Candidate is out as the Wine team hack their way towards a huge new stable release with Wine 5.0 due next year.
Since they're currently in a "code freeze", where they don't push through big changes to focus on stability as they fix up bugs there's no huge new features. There are, however, quite a lot of noted bug fixes this time around.
Of the 46 noted bugs squashed some, like a Blood 2 audio issue, are rather old that were actually fixed in previous releases. Recent fixes include problems solved for: TrackMania Forever, Divinity: Original Sin 2, mouse input improvements, Epic Game Store fixes, Empires: Dawn of the Modern World and more.
You can view the full Wine 5.0-RC3 release notes here.
I expect we will see an update to Steam Play Proton once Wine 5.0 is out and declared stable. It would make sense to wait until then, considering how many bug fixes will be making it in during this time.