Converting a 42.15 save to 42.16

REMEMBER TO MAKE A COPY BEFORE TOUCHING A SAVE'S FILES
The only thing we are changing is removing echo creek as a spawn location so your character should be fine in theory

It is as simple as making a new save and copying that new save's "map_ver.bin" file.
You then just paste the new "map_ver.bin" file into your old save to bring it back

Linux saves are located in /home/(user)/Zomboid/Saves/
Windows saves are located in C:\Users\(your user name)\Zomboid

You do miss out on the new occupation rebalance and difficulty tweaks. So if its an old save that has minor progress, id just restart.

If you have a mod thats outdated and breaking a save, you gotta wait for that mod to get updated, remove the mod, or just restart without the mod.

The devs would probably prefer if you just restarted but its your game to do as you wish with.