I’m debating on ordering the new iPad Pro 12.9. Mine is the 2015 model, with the A9X chip. I worry about future proofing against an iOS update that won’t be compatible with my iPad. However, Apple is still selling the iPad Mini, which of course has the A8. Knowing this, how likely is iOS 13, 14, 15 going to be supported for the A9X iPad? What has happened historically? My thanks in advance.