Along with doubling the max file size of apps, Apple introduced something else today for its third-party developer community.
TestFlight, the Apple-owned service devs use to beta test their apps before submitting them to the App Store, can now do controlled group testing.
Most App Store customers never see TestFlight, but beta testers use it to install unreleased apps and updates after they’ve been invited by devs. Now different groups can be created within TestFlight to test certain builds.
So a group of the press could only have access to more stable app builds while other devs could test more unstable, experimental builds of the same app.
Source: Apple