XP and Vista no longer supported by Steam
Valve has decided to end any remaining support for Windows XP and Vista from January 1, 2019.
January 1, 2019 brought the end of Valve’s official support for 2001 Windows XP and its immediate 2007 successor, Windows Vista. In practice, this means that it is no longer possible to run the Steam client on both systems. To use the service and all the games and apps purchased through it will require us to update the system at least to Windows 7. It is worth mentioning that Steam was the longest-running digital distribution platform that supported Windows XP and Vista.
The decision is dictated mainly by the very small number of users of both systems. According to data from the December hardware survey, only 0.11% of players use windows XP, and Windows Vista was not even on the list.
Although official support ended with the arrival of 2019, Valve has been gradually limiting Steam’s functionality on both systems. This was due to the client's use of Google Chrome libraries, which are not compatible with older OSs. As a result, Steam Chat was not available for Windows XP and Vista users. As a result, almost all social features on Steam were restricted to people who owned one of these systems.
Steam is not the only app that says goodbye to Windows XP and Vista this year. The same is true of the anti-virus software Avast. As of January 1, 2019, Avast also ceased to be supported on both OSs. In this case, however, this does not apply to virus libraries, which will continue to be updated.