The 12-tester requirement
What Google actually requires for closed testing, and the edge cases nobody documents.
What happens if a tester opts out during your 14-day test
A tester leaving mid-test can reset your 14-day closed testing clock. Here is what Google actually counts, and what to do the day it happens.
Does uploading a new build reset the 14-day testing clock?
Short answer: no. Uploading a new APK or AAB to your closed track does not restart Google Play's 14-day continuous testing requirement. Here is what does.
Closed testing vs internal testing: which one Google requires
Internal testing does not satisfy Google Play's 12-tester requirement. Here is the difference between the tracks and which one unlocks production access.