IPhone XS Max Unlocked retail For parts (read)

Product Name: IPhone XS Max Unlocked retail For parts (read)
This phone is for parts because the issue with it is it won't update. I've tried everything. I don't know retail what to do because I can't use it unless it updates. I've had it for 2 yrs. It worked fine until I had the screen replaced and now it's acting up. No cracks. There is is a pic of the msg it gives me when trying to setup the phone. I've used Att and boost on this phone. Imei number is 353105105692834. This phone has been completely paid off. Make me a offer.