Beta vs. Release version control

Hi there,


my app will soon switch to a newer version (from 6 to 7).

Today, I have a release version of 6.1.27 (where .27 is the build number).


In order to start the beta testing of 7.0, I would like to invite my testers via TestFlight, but still want to be able to release newer sub-versions of the current release, e.g. I want to keep the ability to release a version 6.1.28 while version 7.0.0 (or an alpha 6.9.x) is being tested already.


How to I achieve that? Can I just upload a new build with a 7.0.x version number while the App Store will let me upload and release new versions with numbers lower than that?


Thanks to all!