App Page Updates
A test version of an app that is available before its publication. A developer can show different features to user groups interested in new features and check their reaction.
The App Store use TestFlight. Your users will be offered the chance to download a TestFlight app and test your app afterwards. Up to 25 users can test a beta version.
Google Play has built-in tools for beta testing. Using this tool you can switch on AppFollow feedback for beta testers and study their reaction the same way as you do for normal reviews.