Depends on the version of the FSO build inside of the installer, and we are likely to take one of the future builds as a "BWO official build".
When? When the campaign is finished and we decide to pick a build and run with it.
As far as the BWO Demo is concerned, I don't know about the latest FSO builds, but it was working fine for me a year or two back with the then-current FSO build.
When BWO is concluded, the demo will probably also be optimized to work with the same FSO build the entire campaign will be subject to.