The development team at Marvelous Designer has released the Open Beta for the 5.5 version of their software, with a series of improvements and new features including:

Keep track of tasks performed on a 3D Garment. Revert back to and/or save versions of different '3D States'.

Merge the two patterns into a single pattern.
Symmetric Sewing
Symmetrically, sew symmetrically pasted patterns.

M:No Sewing
Sew 'M' number of segments to 'N' number of segments, and edit them as a group.

MCX & Alembic File Export (Alembic on Mac will be available in the official MD 5.5 version)
Animations can now be exported in the MCX format, which can hold larger amounts of animation data and Alembic format, which was developed as an open source library primarily by Sony Imageworks.

Offset Multiple Internal Lines
Generated multiple Internal Lines while using the Offset as the Internal Line function.

Multiple UV Guides
Show and/or hide multiple guidelines when manually adjusting the UV Guides.

At this page you can find all the details on the implementations made in the MD 5.5

To participate in the open beta you must subscribe to their site and download the software.