People still play BP multi? I'm not certain, but BP uses .tbms so It might actually work with the latest release. If it runs clean, that's another story. It's a better bet to run it with WIH.
While there were some informal musings some years back, there are no planned updates on BP multi for WIH2. For myself personally, I'm at a point in my career where my professional life is consuming all other facets, and freespace modding has taken a regrettable back seat.
It is more or less a community project though, so if others want to work on it they can. All our work is still available on the project's SVN and is fully modable. Though I must warn you, finding other freespace multi players, in all likelihood is probably very difficult.