It keep saying unable to install iOS 17

What happens when you try?

Can you post a screenshot of the whole screen, it could reveal why you aren't able to update.

Make sure you:

• Are using a WiFi connection (not a hotspot).

• You have an active cell signal (You need both WiFi and cellular service to perform the upgrade).

• Are not using a VPN connection.

• Have your battery charged at least 50%. Better yet, keep it plugged in during the update.

• Do not have power save mode turned on.

• Do not have a beta version installed.

• You have at least 10 gigs of storage available.

Click on this link on what to do if you can't update your phone -

If your iPhone or iPad won't update – Apple Support (UK)

Check to make sure your iPohone is compatible with the iOS 17 update. Apple only supports iPhones XS Max and newer. So if you’re trying to install the update to a later model it won’t be supported. If that doesn’t seem to work your best bet is two options. Backup and reset the phone. OR schedule an appointment with your local Genius Bar and see if they can detect why it isn’t working. It may also be that you don’t have enough storage on your device.