The new filesystem APIs were introduced with Windows 95, so there was no backward compatibility to break. New programs using those new APIs were forced to suppo

The new filesystem APIs were introduced with Windows 95, so there was no backward compatibility to break. New programs using those new APIs were forced to support spaces in directories. Using spaces in the system directories forced application developers to consider that scenario and deal with it appropriately. Meanwhile, DOS and Windows 3.1 applications that did run on Windows 95 could access files under a backward compatible 8.3 scheme, like C:\Progra~1\ instead of "C:\Program Files".