Just a guess, but it could be that interest in the standard has died down a little bit as an updated OpenPGP RFC is in progress.<p>Anecdote time: In the summer of 2014 I got a bad case of Mononucleosis and decided to implement OpenPGP from scratch. By modern standards, OpenPGP is fairly horrible and as soon as I got an excuse to postpone this project (the new RFC) I did so. :)