Hey everyone!
With operating systems being updated all the time, older operating systems don't get updated anymore. Since Microsoft has stopped supporting Windows XP, Windows Vista slowly phasing out (around 3% of people using Overwolf are on Windows Vista or XP), and the upcoming Windows 10 being a platform update, we at Overwolf made a decision. 
We will no longer be actively updating features for Windows XP and Vista. What does this mean? It means that:
We will continue to test and make sure Overwolf doesn't crash games on Vista and XP
If a feature is problematic with a specific game, we will disable that feature for that game.
New Overwolf features may not necessarily work with Vista or XP.
New games will not be tested on Vista or XP.
We will not fix or enable features that creates issues on Vista or XP .
We will not develop new features for these platforms.
We understand that for some of you this will be a problem, we're very sorry for the inconvenience. The best I can suggest is when Windows 10 comes around, upgrade if you can as we will be supporting Windows 10 in it's entirety.
See you in game,