Each release (meaning what is uploaded to the Play Store) has all known bugs fixed as well as any other enhancements. It's a record of the current version of the uploaded APK.
I have a main folder like "B4A" and sub-folders with my apps. When I create a new version, I just copy the complete app-folder and rename it from f.e. "10" to "11".
When my pc boots, a little script is started to copy the main folder to Google-Drive and two other places to save it.