Blizzard are cutting support for players of several Blizzard games that are still running on Windows XP or Vista.
The news comes from a forum post from Community Manager, Ornyx who explains the move. They go on to explain that the move will take place later on this year on a staggered schedule, going through each game. Once the change takes place, the games will not work on those operating systems and they encourage players to upgrade to a newer version.
The titles that will be affected by the change are, World of Warcraft, StarCraft II, Diablo III, Hearthstone, and Heroes of the Storm.
Microsoft cut support for their XP and Vista operating systems back in 2009 and 2012. At the time those operating systems were still heavily used, but since then there have been three major Windows updates since Vista, and so it makes sense to move on from those systems.