June 5, 2017
After analyses of the APK, It seems like bug fixes were really all that was implemented in the latest Pokemon GO update:
- There is no additional code/features that hint at a new Gym rework :( Only existing code from the last APK datamine...
- Improved system for PTC (Pokemon Trainer Account) login errors. No confirmation if the added features improve stability.
- New variable for each Android version (Lolipop, Marshmallow, etc..). Most likely not related to any new features/mechanics.
Check out the TSR post for more discussion and information.