Given this review: "K-9 Mail client is simply the best and the most versatile way of working with your inbox on the phone. I've been using it since 2009 on a number of Android devices and never had any issues with the app. Extremely fast reliable and configurable doesn't drain battery even with the frequent push-notifications enabled has intuitive interface and does exactly what it has to do. K-9 Mail is also smart enough to recognize necessary settings for the majority of ISPs making the initial setup effortless. Thank you guys for this decent open-source software." Would you recommend this app to a friend? Not at all, No, Maybe, Yes, or Definitely?
Definitely