MS21 is the Gripen E, it takes everything the Gripen have used and builds up from their that’s what the MS is Material (or Mission, I’ve seen both) System
If we get more upgrades to the systems on the Gripen E it will become the MS22
Saab’s Gripen E Fighter Makes Progress At Home and In Brazil | Aviation International News Saab's Gripen E Fighter Makes Progress At Home and In Brazil | Aviation International News
MS21 focus was on air and EW systems that separated it from the MS20 of the Gripen C which don’t have those