https://bugs.winehq.org/show_bug.cgi?id=42000
--- Comment #17 from Olivier F. R. Dierick o.dierick@piezo-forte.be --- (In reply to PeterG from comment #16)
Blizzard are completely removing support for XP and state that the Blizzard app will no longer run unless you upgrade to Win 7 +
Therefore the XP temporary workaround will possibly cease to function in October 2017.
Since Wine 2.17 (or 2.15...2.16 I can't remember) the Blizzard app does work in win7 mode for me.