From what I understand you need to keep updating Xojo each year.
You may be able to use Xojo 2025r2.1 with older Xcode.
Your only way (as far as I know) to support iPhone Duo using Xojo, will be to wait for a future release of Xojo that includes the required SDK.
Yeah, Apple renamed the simulator and now Xojo can’t find it any more. The way to handle this will probably be to make a symlink (or just a duplicate) from the new app to the old name… but if Apple changed any of the protocols, you’ll need to wait until Xojo fixes it and upgrade.