All Rust Servers, even private ones, experience a “forced wipe” by the developers every month. For Steam servers, the type that we offer, that’s on the first Thursday of every month at 2pm ET. The forced wipe removes all changes players have made to the game map across all servers, and while you can manually wipe your server more frequently, this one is mandatory.
Force Wipes are done in-tandem with game updates and will make old maps incompatible with the new version of the game. If you try to restore your map from a backup or the copy the server itself makes, you are more than likely to run into either startup errors preventing the server from starting or terrain glitches as new content tries to function on an old map. Facepunch Studios works with the assumption that the game will be running with a fresh world after each update and there is no built in system to upgrade old maps to a new version.