Thunderbird for Android / K-9 Mail

19.0

New:

Message notification actions can be configured (#3530)
Message font size scales with device preferences (#10692)
Integrate an easily discoverable way to configure and use Thundermail (#10866, #10958, #10994)

Fixed:

Thunderbird crashed on Android 8 when fetching images (#10721)
Accidental swipe in message viewer marked unread email as read (#10747)