A minor update has been issued primarily to help improve overall Steam Deck compatibility and fix frequent freezing on the platform, which is a common issue with older versions of the engine. The engine has been upgraded to a more recent framework, and testing has been done to ensure no other aspects were broken in the process.
As a result of the upgrade, you may be warned when loading old save files that they are potentially malicious due to being created on an allegedly different device. This is a normal security feature of Ren'Py 7.6.3. Select "Yes" when prompted to load a save file anyway, and the file should be loaded normally. Simply save again to dismiss the warning prompt.
Windows, Mac, and Linux PC users may revert to version 1.1 (the initial release version on Steam) without issue if desired. From your game library, open the game's Properties window, then open the Betas tab to opt into the initial Steam release.