Release history
Thunderbird for Android K-9 Mail 24.0
HTML signatures per identity and a reply/reply-all prompt land; Minor UI fixes round out the update
Thunderbird for Android K-9 Mail 23.1
Fixes attachment filename decoding for non-ASCII characters
Thunderbird for Android K-9 Mail 23.0
Identical to Thunderbird 23.0; Fixes single-line signature bug
Thunderbird for Android K-9 Mail 21.1
Fixes Empty Trash action failure
Thunderbird for Android K-9 Mail 20.1
Fixes crashes on long message rendering and memory exhaustion
Thunderbird for Android K-9 Mail 20.0
K-9 Mail 20.0 fixes notification privacy leaks avatars when disabled and improves tablet compose usability alongside UI polish
Thunderbird for Android K-9 Mail 19.2
K-9 Mail 19.2 fixes a crash when scanning Thunderbird QR codes for account setup
Thunderbird for Android K-9 Mail 19.1
K-9 Mail 19.1 adds discoverable Thundermail configuration for easier encrypted email setup on Android
Thunderbird for Android K-9 Mail 19.0
Notification actions are now configurable per-message; System font size preferences apply to message text; Thundermail integration surfaces as a first-class configuration path