Google updated the Play Store Developer Console on April 18, 2017, and as part of this update, the APK page (which was used to create new application releases for alpha, beta, and production tracks) was replaced by the application page.
Managing closed beta testing on the APK page was a fairly simple process, you just select the beta tab and choose from the list of previously added testers.
Since upgrading to App Releases, I cannot manage the tester lists from the page.
As on the Google help page on this topic -
https://support.google.com/googleplay/android-developer/answer/3131213 , I should be able to manage the list of testers in the "Choose a test method" section. However, as can be seen in the screenshot below, this parameter is not:

I have also tried emailing Google in this regard, but have not heard since. :(
Any recommendations or pointers in this regard are welcome.
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