Rather than keeping old systems around (though we do that too, still having 486 systems running), we keep diskless version of old OS versions around, complete w

Rather than keeping old systems around (though we do that too, still having 486 systems running), we keep diskless version of old OS versions around, complete with installed applications (IDEs, compilers etc). Anything from WinXP to Win10 works fine over iSCSI (presumably 11 does too), DOS using etherboot and MSNET, and diskless linux has never been a challenge.