Track

A track is a release channel in Google Play. Every release you publish goes to one, and the four you will use are internal testing, closed testing, open testing and production.

Internal testing is the fast one. Up to 100 testers you name, and builds reach them within minutes with no review wait, which makes it the right place to check that a signed bundle actually installs.

Closed testing is invite-only but larger, using email lists or Google Groups, and you can run several named closed tracks at once for staged QA. This is also the track tied to the production access requirement for new personal developer accounts.

Open testing is public: anyone can join from a link or from your store listing, and the app is visible on Play with a testing badge. Useful for scale, less useful for confidentiality.

Production is the store proper.

The constraint that catches people is version codes. They must be unique and increasing across the whole app, not per track, and a testing track needs a higher version code than production for testers to receive it. Ship production with 47 and your internal track sitting at 45 silently serves testers the production build.

You promote a release between tracks rather than re-uploading. The same bundle moves up, keeping the artefact identical to the one you tested.

See also: closed testing, staged rollout, AAB.