MS has always held that system calls are not guaranteed ABI stable. So any application doing this is subject to breakage at any time. That said I wouldn't be su

MS has always held that system calls are not guaranteed ABI stable. So any application doing this is subject to breakage at any time. That said I wouldn't be surprised if they are doing something not to dissimilar to this for those processes in kernel mode to emulate for things that are out of support and have no living vendor. That said if you look at the list linked above some are "stable" meaning that MS probably knows this happens and kept those specific ones stable. But the rule still applies... never do direct system calls on NT.