to build a new simulator on old code, only to be compatible with old program additions, was in my opinion a very big mistake, which i would not have trusted microsoft with. the work invested so far to get the simulator executable, could have been better used there. then it would have taken 1 year longer until the release, the users would have been more satisfied and this patchwork work would have been avoided. by the old program structure, MS now deprives itself of the possibility to program a sim, which is able to fully use the current and future technology.