The next-gen Thief is expected to launch next year.
Thief 4, or Thi4f as it was labeled by the official Eidos website, is now officially known as simply Thief and will be a reboot of the classic stealth series, according to this month's issue of Game Informer. Garrett is back in action in a "Gothic industrial metropolis," stealing everything that's not nailed down, and will also very likely find himself eventually, and unwillingly, drawn into the religious and political intrigues of the City, which has fallen under the rule of a tyrant known as the Baron and also happens to be suffering the ravages of a plague.
Sound familiar? The Dishonored comparisons are unavoidable, and the new Garrett certainly has more of a mechanical, ninja-like look about him - it looks like he finally got that bow upgrade - but the studio pointed out in a brief preview trailer that the other Eidos Montreal team did a very good job bringing back another much-loved franchise - Deus Ex - and said that the Thief team is determined to prove that wasn't just a matter of luck.
Thief is currently slated to come out in 2014 for the PC, PlayStation 4 and other next-gen platforms. And Eidos has (finally) updated the Thief website, so you can get a better look at what's new at thief4.com.
Source: Game Informer