According to the official twitter, a teaser website of Mahou Shoujo Madoka★Magica secret project was launched. The voices of Madoka are played randomly on the website. New voices will be updated daily. Madoka says "Everyone, a little miracle may come true." "Let's do Mahou Shoujo together once again."
Link:Madoka Magica Secret Project
The content of the secret project regarding a new development of Madoka Magica will be announced soon.
Source: Madoka Magica official twitter