If they have an update that they consider important enough because of an issue with the version you are currently on, you can get an update.
That is how I got mine updated when it was a long ways out of warranty.
It is odd that you were not notified though. I had Tandem send me emails, and my local Tandem rep called me, more than once.
And I still have them bug me now and again to try and get me to get a new pump.