The new patch, their first major patch which is being called their “biggest update yet“, includes the ability to, among other things, “restore your game to prior states with just a single click. Game updates are now not only optional, but also reversible.”
The patch also includes “much-requested improvements to the friend system (making it easier to find and invite friends), pausing & resuming downloads, extended pre-installation options with more ways to configure your games, and an improved app UI and navigation.”
The patch has been made available right now to all those using the GOG Galaxy service and are subscribed to the preview updates. It will roll out to all users “very soon”.