If you’re hoping to experience Gielinor in all its glory, here’s how to use the popular new OSRS HD Client. Instead, you’ll need to download a third-party client known as RuneLite, then download and install the custom HD add-on. Running Old School RuneScape isn’t as easy as logging in and toggling on a High Definition option. The update didn’t arrive without controversy, however, as Jagex had originally put a stop to the third-party client - before community backlash led to its full blessing from the developer. It took a few decades, but Old School RuneScape is finally playable in HD.