Sorry but why on earth would you want to do this? Mod4Win was maybe great for its time but compared to today's playback routines it leaves much to be desired in playback accuracy - you'd have to catch up on over 20 years of accumulated knowledge that is found in libopenmpt, libxmp, BASS and all the other module decoder libraries out there. It's really great that the code was released for preservation purposes, but it makes zero sense to revive this particular player and port it to a modern operating system. You can throw away practically all of the relevant code (in particular the 16-bit GUI code which cannot be reused as-is when developing for Win32, and of course code written for sound cards such as the Gravis Ultrasound or OPL4 chip will be impossible to run on Windows 10) and start all over if you want to have a modern Mod4Win, at which point you could just take libopenmpt and practically any GUI framework to create a lookalike player.
Windows 3.11 and Windows 11 may have "Windows" and "11" common in their name - but that's about it. There is no straightforward way to update a multimedia application from one of those two systems to the other.
