Thank you cketti. As an addendum, if you want to prevent the play store from updating it at all you can get the APK from f-droid instead of github (K-9 Mail | F-Droid - Free and Open Source Android App Repository).
Thank you cketti. As an addendum, if you want to prevent the play store from updating it at all you can get the APK from f-droid instead of github (K-9 Mail | F-Droid - Free and Open Source Android App Repository).