Over the past two years, we've had around 3-400 beta testers. After Apples update to TestFlight the summer of 2017, we've had problems with nearly all our TestFlight-uploads. Sometimes our beta testers receive email/notification about "a new build is ready to test" 90 days too late, at the exact time the build expires, and sometimes they don't receive notification at all. Just a handful of times it works as expected, that they get notified when we the build is available to test.
Is there a secret trick to managing TestFlight? I upload the build, click "provide export compliance"-thing, add my internal and external group, and click "Start testing". The build automatically gets available for internal testing, and is sent to beta-review for Apple for external testing. They approve it within 24h, and the build is available in the TestFlight-app for all our beta-testers. But none of them got a notification saying there's a new build..
Followup: How can we fix this now? Do we have to upload a completely new build, or can I remove the "external testers"-group from the build and re-add them again. Will they receive a "new build available"-notifications? Will they also receive "Build is no longer available for testing" at the moment I remove the external group from the currently active new build? Meh..