End user does not need to download it again but if you are a addon
author you must download this new SDK, somes bug were cleared
and it support now multi dock EVA (see ISS UMMU addon in DGIV
more download for an example)
Download and install "Universal MMu 1.5" run installer
and you'll find the new SDK in the doc folder.
http://orbiter.dansteph.com/index.php?disp=dThe new function for Multi dock is "SetActiveDockForTransfer" in the SDK header.
Happy Mmuing
Dan