Downgrade apps already installed just need the old APK file!
Since I realized you *can* downgrade your apps (install lower version over actual (higher) version of app) using android feature "pm install -r -d file.apk" yesterday, I got time and wrote small and simple app which does everything for you. Just pick APK and click on Install APK. That's it! -Pyler
(*ROOT NEEDED*)
-Have the apk you want to downgrade at HAND!
-Make sure you the app you want to downgrade installed already.
-Click select APK (The older version of the app)
-Then click install
I was give permission to upload this app on the Google Play Store.
Credits: Pyler (He made the APP! Thank him on XDA).