A security vulnerability found in the Unity engine, which had laid dormant for almost a decade, was recently patched. Games made using the engine also need to be patched, however, so expect a lot of games you wouldn't expect to still be receiving updates to suddenly download one out of the blue. Overcooked 2, for instance.
Microsoft, which owns so many videogame studios it's hard to keep track, has announced that some of its games will be temporarily pulled from storefronts while patches for the vulnerability are worked on. Which is why, if you look for Fallout Shelter, Pentiment, Wasteland Remastered, or Wasteland 3 on the Steam store right now you won't find them. If you own them already you still have access to them, though Microsoft suggests you "should temporarily uninstall the app."
