If you are on Windows and trying to downgrade, you must fully uninstall your current version of iTunes first. This includes uninstalling:
Older versions have security vulnerabilities and may not sync with iOS 15 or later. Only downgrade if you understand the risks. download older itunes
and follow the prompts.
Many users seek because it is the last version that allowed installing and managing iOS apps from the desktop. If you are on Windows and trying to
(choose one):