How to downgrade to the "good" version (before this silly UI update)?

[jimimaseye]

If you want the actual k9 v5.600 (and without risk of overwriting by google play):

How to downgrade to an earlier version?

Android does not support downgrading an app. So you have to uninstall the app, then install the old versions you want to continue using. Before doing that, you probably want to export your settings, though. Export K-9 Mail settings Open the drawer Select Settings Select Export settings Tap the Export button Select a destination and tap the Save button Disable auto update in Google Play Open the Play Store app Go to the details page of K-9 Mail Open the “three dots” menu in the upper rig…

Use the F-droid route - you won’t have to worry about google play as it will be seen as a 3rd party install.