Agh, sorry. Problem solved! I was on ver 4.2.9, but had auto updates running so I assumed that it would have picked up the latest... but it was set to check "weekly" and the week wasn't quite up yet, so it hadn't looked. My poor assumption!
Perhaps a feature suggestion though -- if there is a way to detect that the OS version has changed, perhaps have it run an auto-update immediately?
Anyway, thank you!