How to add new Device UDID to an existing provisioning profile in the new pattern

Question

I just want to add new device UDID to an existing provisioning profile, to mod

Answer 1

Note that testers are no longer added via UUID in the new Apple TestFlight.

Test Flight builds now require an App Store Distribution Provisioning Profile. The portal does not allow UUIDs to be added to this type of provisioning profile.

Instead, add "Internal Testers" via iTunes Connect:

Internal testers are iTunes Connect users with the Admin or Technical role. They can be added in Users and Roles.

After adding a user, be sure to click on their name and flip the "Internal Tester" switch.

Then, go to App > Prerelease > Internal Testers and invite them to the build.