iPhone unavailable

If you forgot the passcode on your iPhone, or your iPhone is disabled or unavailable -

How to reset your passcode without a computer if you have iOS 15.2 or higher.

How to remove your iPhone, iPad, or iPod touch passcode without a computer - Apple Support

How to reset your passcode using a computer.

If you forgot your iPhone passcode - Apple Support

tuitavua99 Said:

"iphone unavailable: how can we available my iphone and my serial number is[...]"

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Updating an iPhone XS iOS 16:

Update the iOS Using a Computer:

• Use my User Tip:  Update your iPhone Using a Computer - User Tip
• IMPORTANT: If you have an option to update, however, then be certain you backup your iPhone first. That way, you will have something to restore your iPhone from should anything go wrong with the update