Sony's quietly released PS Vita firmware 3.01, a minor update that aims to improve system stability. Beyond that, there are seemingly no other changes. It's available now for download on Network Update. We've included a manual install link below.
It's worth noting that the update does appear to be mandatory - accessing the PlayStation Store, or any other areas walled off by a PSN login will prompt a system software update.
That said, given the timing and mandatory nature of this update, there's a chance that it is related to the recent round of PSN maintenance that just wrapped up.