The most recent version of the application available on itch.io is 2.5.4, updating from there can get you to 2.5.4_3. The most recent update listed in the application's internal updater is version 2.6.0 and claims 2.5.4_3 is an "incompatible client" because the client revision is 3 but the minimum declared client version required to update to 2.6.0 is 200, which is obviously impossible. The tool tip when hovering over this error says to resolve this by downloading the latest client from itch.io or the Microsoft store but the versions on those platforms is only more out of date and obviously not going to provide a client version of 200. Either the 2.6.0 update is demanding a client version of 200 in error or the itch.io files offered and Microsoft Store need updated to serve the newer version