Many of Blizzard’s older games have had continued support from the company when it comes to older systems. Unless forced to, many PC gamers have hung on to platforms like Windows XP due to their compatibility and flexibility compared to newer operating systems. However, the time has come for Blizzard, and arguably Blizzard fans, to move on.
As confirmed by Blizzard community manager Nate Valenta, Blizzard will begin to drop support for World of Warcraft , StarCraft II , Diablo III , Hearthstone and Heroes of the Storm for anyone trying to play these games on Windows XP or Vista. This end of support will begin in October.
Valenta notes that Microsoft itself dropped support for these operating systems in 2009 and 2012 respectively, and that Blizzard only continued to do so due to the volume of players still using them. People have generally moved on at this point, however. The “vast majority” of Blizzard users have upgraded on to one of several newer opperating systems.
Blizzard will be staggering this process out game by game and providing more notices as the time comes for each title. Blizzard not supporting these systems does mean that the games will no longer function on them, so fans have been encouraged to upgrade as soon as possible.
Source: Blizzard