BRG's CTO responded to my email a week ago regarding patch #1:

"As it happens we are about to release a second patch, and we are combining both patches together to release at the same time on GOG. You should see the patch in the next couple of days."

The following have been confirmed:
- Checkpoint saving (may be delayed; see post below)

What is the patch... patching?

Everything from Patch #1 (see Steam Communities), and most likely more scripting/crash fixes.

Looks like Steam just got another update, but checkpoint saving isn't in it.

Was hoping one of the patches would have made it by now. I'm getting crashes and the likely cause is more than 6 cores. Seems to crash right before an in game cut scene, without checkpoints you can imagine how annoying this is to replay the entire mission.