On April 24 I must start using a new Xcode to build iOS
Every time I am forced through this process, it’s a nightmare.
Can anyone who has done this recently warn me/advise me of what the best way to keep Xcode and Xojo working when the dust settles?
Requires Xcode 16 and iOS 18
Im currently building with Xojo 2024 and Xcode 15.4
Looks like you need Xojo 2025r1 (or later) too:
#78580 - Update to iOS 18 SDK
Make backups of all your dev certs, including private keys. Just in case you need to reinstall them.
What are your learning from previous nightmares? Only if you know that then you can prevent problems at the next update. I only skim your messages and you always have problems when you wan to make a new version of your iOS app.
That nothing can be expected to upgrade smoothly , and that sooner or later I will probably abandon iOS altogether. 
The iOS development system is incredibly fragile and over complicated.
(Probably the same description could be levelled at me)
Well, that is true for all macOS applications where security becomes dumber by the year.
I try to add more checks when something fails. I have an IDE script which - for whatever reason - wasn’t done in a build. I added a check just to notice on the next fail that prints in IDE scripts don’t work when the script is run by the IDE Communicator. But there is always a new hole in the process.
Upgraded Xojo - all working.
Tried to update Xcode, but no update available, so I now need to upgrade my MacOs to Sequioa and then do Xcode.
See y’all on the other side if it works.. 