Can I use one save with the next experimental version of the game? For example, can I use a save game created in version Feb. 21 and saved in Feb. 21 with the Feb. 23 version? If so, what do I need to copy?
Also, does this work if one game came from a Windows system and goes to a Linux distro?
Recent saves (recent as in 6 months old) are only rarely, if ever, rendered broken by the experimental updates. Some bugs might occur ocasionally, but generally those only affect your opre-update items, and not general gameplay or the newly versions of said broken items.
Dont know about switching saves between the operative systems
no problem, unless you get wersion with enabled desert mapgen and you go on map with that mapgen when its dissbaled
you can even jump from stable to experimental but some bugs may happen (and its not to rare too)
Backwards compatibility is a feature we try and maintain whenever reasonable, including saves from the previous major version of the game (so 0.C should read saves from 0.B, 0.B should read saves from 0.A, etc) and all experimental versions should load saves from the previous major version.
If you do encounter an issue where a new version of the game can’t properly load a save written by an older version, please feel free to report it as a bug, we’ll try and get it to load properly, and in the worst case will get you a workaround. “Properly” here includes “minor” things like items disappearing, missions getting cancelled, items showing up as undefined as well as crashes or total inability to load the saves.
If you bounce back and forth in versions you’re on your own though, forward compatibility is much harder to maintain than backwards compatibility, and I doubt it’s worth the effort in this case. Please let me know if you have a use case that requires forward compatibility and we can consider supporting it, but it’d have to be a pretty good reason.