It's not limited to MS either. Running "cc" on a modern linux box still accepts 35+ year old K&R code by default. The bourne shell has been officially standardized since POSIX 25 years ago, and as a practical matter has been backwards compatible much longer than that. Xlib code from 1987 still runs unmodified...
Yeah, and I don’t actually believe in backward compatibility when it comes to programming languages. If you want forward compatibility, make a good cross compiler from n to n + 1. If you want backward compatibility, make one from n + 1 to n, if it’s reasonable.
The bourne shell has been officially standardized since POSIX 25 years ago...
...and the maintainer of the Vim syntax highlighting module for Bourne Shell scripts still refuses to default to POSIX mode, because some OSs still ship with a pre-POSIX /bin/sh. grumble grumble grumble
