- What's the best open source mail client? - K9
- What's the the problem with K9? - The design.
Because of that I decided to fork K9 and give it a material design. I used the most recent stable release (5.010). I only changed the theme to material (see screenshots). I didn't remove or add functions.
The app is, as you know, complete open source. So here is the source code of my fork.
Changelog (K9 Githubsite)