Thunderbird for Android version 15.0b1, based on K-9 Mail. Changes include:
- Add avatar to message list content
- Enable in-app notifications for beta
- In-app error notification improvements
- Default sync interval changed to 15 minutes
- Warn user in compose when no sent folder detected
- Confirm when sending message without sent folder
- 'Colorize contact pictures' default changed unexpectedly from true to false
- Displaying IMAP password in did not prompt for authentication