Your Project Zomboid hosting server has automatic saves after you leave the game. Even if the game version is changed (updated), your saves are converted to the new version. However, if you want to share your server's save files or make a backup just in case, you can find Project Zomboid save game file in the following folder:
C:\Users\Yourusername\Zomboid\Saves\Multiplayer
Under this path there will be two folders "servertest" and "servertest_player" or as you specified them when setting up your server, during creation.
TIP
If you have not yet created your own Project Zomboid server and want to, click on the articleto learn how to do it
You can simply copy these folders to a safe place and if something happens to your gaming experience, you can replace them with the backed up files.
Project Zomboid how to save the server, backups using the GODLIKE panel