diff --git a/browser/api/lib/auto-updater.coffee b/browser/api/lib/auto-updater.coffee
index fc29bd3d964..81c22f16d57 100644
--- a/browser/api/lib/auto-updater.coffee
+++ b/browser/api/lib/auto-updater.coffee
@@ -5,7 +5,7 @@ AutoUpdater::__proto__ = EventEmitter.prototype
 
 autoUpdater = new AutoUpdater
 autoUpdater.on 'update-downloaded-raw', (args...) ->
-  args[2] = new Date(args[2])  # releaseDate
+  args[3] = new Date(args[3])  # releaseDate
   @emit 'update-downloaded', args..., => @quitAndInstall()
 
 module.exports = autoUpdater