Windows Phone updates have always been a murky situation for users. Unless you read about an update, you may never be notified about an update due to Windows Phone’s somewhat iffy updating tile.
We’ve just recently noticed a subtle change to the Store that should be pretty helpful in alleviating this confusion. The Windows Phone Store website and app in Windows Phone 8 now display the timestamp of the app’s last update. For example, on the Skype app listing you can check if you have the latest version (seen above).