TestFlight: Use multiple devices

To have multiple devices with test flight do the following:

1. Make sure ALL TestFlight apps on all the devices are signed into the SAME Apple ID. (Note that the device can be signed into a different Apple ID.)
2. Open the invitation email on the first device to add the app to Test Flight.
3. Go to iTunes Connect -> Your App -> “TestFlight” Tab -> Internal Testing and remove your internal tester.
4. Click “Save”
5. Re-add the internal tester.
6. Click “Save”
7. Open the invitation email on the second device to add the app to Test Flight on that device.

Note: You can use any email address and any app or website for accepting the invitation email.