Just rolled out an update most of you will probably (and hopefully) never see 
If a system hasn't been updated in over 14 days, it will now display a message informing the user of the situation and helping them update the system:
The partial upgrade info notification now also features the same update system button.
In general, it's my goal for GSM to stay out of the way as much as possible, so I hope >14 days doesn't trigger for too many experienced users who just don't update regularly. Of course, you can always just turn the notifications off 