With the release of Update v0.7.5, save files from version v0.7.2 (before November 2024) are no longer compatible.
Ships At Sea is in Early Access, and since Update v0.7.5 (late November 2024), we have made significant changes to the game's core architecture. As a result, older save files from v0.7.2 will not work with the latest version, requiring players to start a new game. If a save file is marked as incompatible, it cannot be upgraded to work with the new version.
The good thing about the new profiles is that you can now carry your certificates, XP and skills over to a new game. Previously, all progress was tied to the savegame, meaning you'd have to start from scratch every time you wanted to join a multiplayer session or start a new singleplayer game.