Apple recently released iOS 16.1, and as is traditional, Apple has now stopped signing the previous version, iOS 16.0.3, making downgrading to that version of iOS no longer possible.
iOS 16.0.3 was a smaller bug fix update that addressed bugs that were affecting iPhone 14 and iPhone 14 Pro models.
The recent iOS 16.1 update that replaced it introduced iCloud Shared Photo Library, Live Activities for the Lock Screen and Dynamic Island, support for the Matter smart home standard, Clean Energy Charging, and more.
The new software can be downloaded on compatible devices over the air by going to “Settings” -> “General” -> “Software Update.”
Falling back to an older iOS build is often used by users that jailbreak their iPhones. Restoring an iPhone or iPad to a previous version of iOS can also sometimes be helpful for users who experience significant bugs after upgrading to the latest version of iOS.