At the moment, all we can say is that multiplayer is on our list of wanted projectgoals. If, and when the multiplayer code will be restored can unfortunately not being answered at this point of the development. It really depends on the complexity of the issue, and the amount of time the current and future coders can invest into that issue.
Honestly, it's not really quite on top of the list yet. First off all, I want the graphic and functionality enhanced. But the multiplayer code will certainly not be forgotten
Sorry for not having any better news for you at this time
(edit) I might be mistaken, but if you and your friends do own the disk version, try MC 2.5 with it. AFAIK Magic tried to stay compatible with the retail. At least at this early point of development, there is a chance that it's still working. But the more our work grows, the more grows the gasp to the retail, so sooner or later it would break anyway.