I got that as well this morning. Then I got a message saying the game updates, but the version number has actually gotten older rather than newer. I've been emailing back and forth with their support team about a crash on startup, so I've actually got the version numbers to check. The unknown game version thing was for V2.2.6.3150. Now it's back to V2.2.4.3141.

Yes, the game version has ben reverted. Probably the last updates are basically for the expansion and It messes something in vanilla games. Just guessing. No idea.