PMDG was last week forced to delay the NGXu Expansion pack. Today, it has been released as Robert Randazzo promised.
Except for the expansion pack, the base package has been updated to be compatible with the 600 and 700 versions of the aircraft. Update of 2.91.0121 of the NGXu includes some fixes like with the wing flap calculator had visible blue pixels, updating the panel states to reflect and much more. The update is available through the PMDG operations centre 2.0. The update is required if you want to install the NGXu expansion package.