Fully functional on LG G3 but... RECENT ISSUE - There's a bug that causes the screen to scroll up unpredictability whenever you zoom in...its maddening. I will try to reinstall. K9 is the only Android email client that I can tolerate. It's ugly and slightly confusing when using the back button with multiple email accounts. But the back button is more of an inherent problem of Android's than with the app. Except for this recent bug  it's a usable email client that I use because there aren't any better alternatives atm.
March 01 2016