***WARNING: THIS APP HAS KNOWN VULNERABILITIES AND HAS NOT BEEN UPDATED IN OVER TWO YEARS*** This was a great system when it was regularly updated. However  it hasn't been updated in over 2 years. OpenKeychain is a fork of APG that is much more currently updated. I have switched to that system. Changing over k9mail is pretty straightforward; the crypto provider just needs to be set to OpenKeychain in each account. Don't get me wrong. I loved its seamless integration with k9mail. It's just that I need something that isn't going to be full of vulnerabilities because of simple lack of updates. APG paved the way  but it seems someone else needs to take the torch (and OpenKeychain seems to have done it).
August 08 2016