The official WP 8.1.1 update for Ativ S released by Samsung. You need to be on official GDR3 to receive this update. To get it, open SamWP8 tools > Tweak > region to “000-AT”. Then check for updates on your phone (Settings > “Check for updates”).
New Update details:
If you’re currently on the dev preview you can flash an 8.0.3 build to get the update.