In some embodiments, a system is provided, and computer-executable instructions cause the system to: obtain, at an edge server of a content delivery network, a request for a content item from a client device; determine that the there are multiple versions of the first content item that require varying amount of resources to serve including a first version, and a second version requiring more resources to serve than the first version; select the second version; send the second version; determine that the client device is not properly rendering the second version of the content item; and in response to determining that that the client device is not properly rendering the second version, send the first version.