cannot activate iphone 7 - message states" Unable to Activate" update required

Read again -> Related Article -> If you can't activate your iPhone or iPad (Wi-Fi + Cellular)

• If you get an error message on your computer that says that the SIM card isn't compatible or is invalid, contact your carrier.
• If you still can't activate your iPhone or iPad, contact Apple Support.

See also this Apple article: If you see No Service or Searching on your iPhone or iPad

If you see No Service or Searching on your iPhone or iPad - Apple Support

👉 iPhone 7 Repair Program for "No Service" Issues

iPhone 7 Repair Program for "No Service" Issues - Apple Support