Full notice here: http://leaf-labs.squarespace.com/news/2015/3/27/maple-end-of-life-notice
The short version:
The time has come to officially end-of-life Maple. The forums will remain open for the foreseeable future, since many of you are still out there hacking on libmaple and various STM32 variants. Thanks for all your support over the years, and feel free to ping us with any questions.