Mastercam X6 Mu3 is now available to Maintenance customers.
A Maintenance date of 6/30/12 or later is required.
This update installs on top of X6 Mu2. So that means you need X6 installed, then the Mu2 update, then apply the Mu3 update.
Mu3 Update is mainly a translator update and includes support for: SolidWorks 2013 files, SolidEdge ST5 files, Rhino v5 files, R23 of the ACIS format.