Bishop Williamson described a Motu Proprio that was to come out soon, back in August. There was also talk from Bruno Volpe of a Motu Proprio touching on the current talks between the SSPX and Rome. Bishop Williamson also mentioned this talk as we reported. No sooner this than that denials came forth by Society Superior Bishop Fellay that there was any such Motu Proprio in the future.
The current one in the works looks like it will touch on the Mass, and there's no indication that it will deal with the SSPX at all, but we'll see more when it comes out. Here's an excerpt from Rorate Caeli.
The document, which will be published as a motu proprio, is the result of a long development - it has been reviewed by the Pontifical Council for the Interpretation of Legislative Texts and by the offices of the Secretariat of State - and is mainly motivated by the transferral of competences on matrimonial matters to the Roman Rota. ... Foregoing this [competence], which will be passed on to the Rota, the Congregation for Divine Worship will not occupy itself, in fact, with the sacraments, and will keep solely its competence in liturgical matters.
According to some authoritative rumors, a passage of the motu proprio of Benedict XVI could expressly mention that "new liturgical movement" of which Cardinal Antonio Cañizares Llovera has spoken in recent times, when intervening in last November's consistory. ...
The Congregation for Divine Worship - which some would wish to rechristen as "of the Sacred Liturgy" or "of the Divine Liturgy" - will henceforth busy itself with this new liturgical movement, including the creation of a new section of the dicastery dedicated to sacred art and music.