I want to test different versions of Google Play Services and I am wondering if it is possible to downgrade the Google Play Services version of a device?
If you are content to try each version at a separate boot and the above doesn't fulfill you're requirement, you'll have to go the full uninstall and install route.
If you truly want to compare, you'll have some problems getting more than one version present at the same time without source code access. I assume you're already in Developer mode. For more guidance, I suggest you look at others who are trying something similar and the links provided. Here's one example: How to keep two versions of an app installed?
Found a solution for those unable to fix google play services in android (e.g. China ROMs) ~ due to bootloader problems etc:
- Reboot your phone to recovery mode using power-volume up
- Use power button to select factory reset, clear data and cache, confirm.
- Reboot to factory reset and without cloud restore reinstall google play services (e.g. in Redmi phones install with china ROM google play store)
- Install all google parts such as normal google PlayStore. Then install apps in google as needed
- Re backup the phone on cloud and you're set.