OS/2 initially developed in cooperation between Microsoft and IBM back in the 1980s had a turbulent history over the years. By 1996 with the final retail release of OS/2 Warp 4.0, IBM conceded defeat by Microsoft realising it was not able to compete with Windows 95, although still managed to withhold a portion of the enterprise market. Years later it was still found on some servers and even ATMs on the street.
OS/2 Warp 4.52 was the final version by IBM released in 2001 with official support ending in 2006. It wasn’t offered in a retail package, but for those who had a contractual agreement with IBM for OS/2 support. After this the foundation of the OS had evolved into what is now known as eComStation.