Apple provides information on security fixes of iOS 16.3.1. Having these issues in mind Apple now no longer supports downgrading to iOS 16.3 and previous releases.
Apple Support: About the security content of iOS 16.3.1 and iPadOS 16.3.1
- Apple Stops Signing iOS 16.3 Following iOS 16.3.1 Launch, Downgrading No Longer Possible
- Apple reveals multiple new security exploits that were patched with iOS 16.3 updates
Developer:Prevent devices from upgrading if iOS 16.3 support is necessary.
QA engineer:Prevent devices from upgrading if iOS 16.3 support is necessary.
PM/DM:Business as usual.