While we don't yet know the new iPhones Apple will be dropping this fall — though there are iPhone 17 rumors — we do know, per Apple's site, that the phones listed below will be compatible with iOS 26. Basically, if you have an iPhone that was announced in 2019 or later, you're in the clear:

The newest iPhone software release could be the last big update before Apple moves to the next-generation iOS 26. Here’s what’s in it.