Error code

Android INSTALL_FAILED_VERSION_DOWNGRADE

ANDROIDINSTALL_FAILED_VERSION_DOWNGRADE
Android Error Code· An error code shown by Android or the Google Play Store.

What it means

The APK cannot be installed because its version code is lower than the currently installed version.

How to fix it

  1. Uninstall the current version first and then install the older APK.
  2. Or obtain the correct newer or equal version of the APK.

Not affiliated with Android. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.