Windows for Workgroups 3.11

Windows for Workgroups 3.11 (originally codenamed Snowball) was released on August 11, 1993, and shipped in November 1993. It supported 32-bit file access, full 32-bit network redirectors, and VCACHE.386 file cache, shared between them. WFW 3.11 dropped standard mode support and requires a 386 machine to run.

A Winsock package was required to support TCP/IP networking in Windows 3.x. Usually third-party packages were used, but in August 1994, Microsoft released an add-on package (codenamed Wolverine) that provided TCP/IP support in Windows for Workgroups 3.11. Wolverine was a 32-bit stack (accessible from 16-bit Windows applications via WinSock Thunk), which gave it superior performance to most of the third-party TCP/IP Windows stacks available. However, it was only compatible with Windows for Workgroups 3.11, and lacked support for dial-up. Wolverine stack was an early version of the TCP/IP stack that would later ship with Windows 95, and provided an early testbed for the 16-to-32-bit compatibility layer that was crucial to Windows 95's success.

Following the release of MS-DOS 6.22 in 1994, WFW 3.11 largely replaced Windows 3.1 for OEM installations on new PCs due to its improved capabilities and greater stability.