- Windows 2.1 (Wikipedia)
It was released with two different variants with differing CPU compatibility, also known as Windows/286 and Windows/386, so the versions are considered to be similar to its predecessor. In comparison, the Windows/386 variant is considered to be better than Windows/286, since it provides support for EMS emulation and is designed to use both conventional and extended memory. Changes to the user interface did not occur in this version, and rather, its performance was increased and enhanced memory management was added. The version is also noted to be the first one to require a hard disk drive. A minor update version, Windows 2.11, was released in March 1989.