TestFlight is now legacy TestFlight and the new Apple version, as accessed via iTunesConnect, is TestFlight Beta Testing.
TestFlight Beta Testing has both increased the number of users to 1000 and reduced it to 25.
The number of internal testers is set to 25. This allows these users to test the app before the extra stage of submitting a test build to Apple for testing. Once submitted to Apple for Beta App Review, the app can be sent to up to 1000 external users. This has had the impact of reducing internal testers from 100 to 25. With additional internal testers needing to be setup as external testers as part of a beta phase rather than a testing phase.
The difference between testing and beta could be significant for some organisations. The Beta App Review checks that the app fully complies with App Store Review Guidelines. This may require more care and attention than a typical beta app deployed via TestFlight.
The Information section allows you to enter a description of what to test. This appears in the TestFlight app as part of the install process. This should be used to give the testers some pointers on new features and changes to focus on. You will also specify the Feedback Email address that is used within the TestFlight app to gather feedback.
There are no tools to manage the setup of 1000 external users although a CSV import of email addresses is possible. Recruitment must be done via email, not via a URL link. This does importantly remove the need to know a users UDID number. But it does also leave a significant gap (opportunity) for tester management tools.
As a developer you can have up to 10 apps at a time in testing (per iTunes Connect account).
As a tester, there is no limit to the amount of number of apps you can test, or developers you can test for. Each tester can test on up to 10 devices.
Test builds are only available for 30 days. Updates for new builds are sent automatically. Only one pre-release version at a time can be tested.
TestFlight Beta Testing is only available for iOS 8 devices so any device compatibility testing must still be deployed via legacy TestFlight.
It’s no longer possible to create an account in legacy TestFlight and messages are appearing within the service to move you over to TestFlight Beta Testing where possible.
This is a major step forward in allowing many more users to be involved in the beta testing phase of an app by removing some of Apple’s limitations. But, it has not yet implemented the full feature set offered by legacy TestFlight.
iTunes Connect Guide