Not since 2009 came more nor official information or rumor important Thief 4 related, but today some professional profiles arise that would obviously be time to work on this fourth installment of the series but they also declared the game engine used for development: the Unreal Engine 3 by Epic Games, commonly used by major brands that multiplatform titles without high costs due to its spreading development environments. As for the gameplay, other members of the development team have stated that there will be a multiplayer sector.

Linkedin profiles that treat the use of the Unreal Engine are those Stephane Bonetti 's, the senior technical level Eugene Kuczerepa designers and Pierre-Claud Jacob ; Colas Fievet and senior level Marc Freveau designers have instead stated online presence in the game with the latter that would create the level "the city".

Waiting to bring official information, probably from some important fair, these rumor we ensure that the development team has never stopped working for Thief 4 to, which should be a fund online (cooperative or competitive) that would support the single player experience and that probably the recent agreement between Square Enix and Epic Games, the title uses the Unreal Engine 3 instead of a proprietary engine modified appropriately.