GTA 4 Is now backwards compatible on Xbox One

All the DLC released also now backward compatible

Grand Theft Auto 4 and its two standalone DLC episodes are now playable via Xbox One backwards compatibility. If you had save files for the original games uploaded to the Xbox Live Cloud, they'll be waiting for you as soon as you start playing.

All of the various and sundry releases for GTA 4, The Lost & Damned, and The Ballad of Gay Tony are supported whether you owned them digitally or on disc. They're also available for purchase on the Xbox Store.