I no longer wish to use my old iPhone 3GS.
I used to use my Apple-ID to log into The iTunes & App Store on it.
Since I use that Apple-ID for iTunes & App Store on several other iDevices, I want to completely deauthorize and unregister the iPhone 3GS from my Apple-ID.
I have already signed out of iTunes & App Store on it. Can and should I "deauthorize" it in any other way?
I no longer use the iTunes program on any computer, so the iPhone is not connected or synced to any computer of mine . (And I don't want to install iTunes, I don't like the program).
Best Answer
You should explicitly deauthorize it. The standard way is to use iTunes.
But if you do not want to install or use iTunes, you can get Apple Support to help you: