I have spent nearly an hour trying to get my iPhone 7 with iOS 15.8 to be recognized within xCode 26. I did not have this issue with the previous version of xCode. I have tried rebooting my Mac, rebooting my iPhone 7, removing the iPhone 7 from the list of devices that belong to my account, verified that I have support files for iOS 15.8 installed, signing out of my Apple account and signing back in....nothing works. Every time I go to "Windows > Devices" I see the iPhone 7, but I get a never-ending spinning circle next to the iPhone 7 (which is shown as connected) along with a banner that says "xCode will continue when Joe's iPhone 7 is finished." I can leave the phone connected to my Mac for an hour, and this message and the spinning circle next to the iPhone 7 never changes.
Impossible to connect iPhone 7 (iOS 15.8) with xCode 26
Since the minimum of deployment version that Xcode 26 supports is iOS 15.0, according to Gemini, I suppose, it should recognize your phone. And you are not able to run the iPhone 7 Simulator?
15.8 isn't available as a platform in xCode, but 15.5 is. Yes, the iPhone 7/15.5 simulator works, but that doesn't resolve the issue with connecting a physical iPhone 7 with iOS 15.8 repeatedly fails.