previously I tested it on iPhone 15 Pro (OS 18.3 and the simulator (various versions), indeed that does not work. I tested on a sandbox account an a separate US account, neither luck. After your comment I also tested on iPad Pro (6th generation) with an M2 (iPadOS 18.3), neither luck for sandbox or US account. All devices are supporting Apple Intelligence. Are you using a VPN or something else? Makes development of applications not easy if not running on iOS or simulator.

Hi Frank, @FrankSchlegel , thanks for the answer. I know it is available on macOS, and is working on my device. However, tried on iOS (simulator and device) with a sandbox account located in the US and language US English set, but that does not work.

In case I would like to downgrade Xcode, that is not possible using MacOS 15.1, as it requires a newer Xcode. For that I need to downgrade also to macOS 14, which is not that easy and risky. Additional, need to downgrade phones and devices, which are currently on 18.1. So in the end, a lot of effort for a silly bug that the Xcode can no longer detect attached devices. While Finder, iTunes and other applications all can see the attached devices and its content.

Hi Claude, I do not know where in X-code you can de-register and register a device, but I disabled and enabled my device under my account in "Certificates, Identifiers & Profiles" part. Note that the device will be only removed once a year, so you can only disable and enable it. That neither did help.