Update: The Steam page for XYK's Team Fortress 2008 mod has been pulled. As reported by Eurogamer, a screenshot from the project's Discord (also now shuttered) suggests Valve could not be convinced at this stage that the TF-2008 team has created a mod for the original game, and is "not just repurposing leaked code".
As also reported by EG, it appears creator XYK left the project's Discord server with a distasteful parting comment.
Our original story follows.
Turn back time with XYK's Team Fortress 2008—a TF2 throwback mod that "reverts the game back to its 2008 version".
Due on Steam on January 11, 2019, its creator says the SourceMod is an alternative to Valve's esteemed Team Fortress 2 and is designed for "those who prefer the game before most of the later updates, and want the simpler old interface."
As reported by Eurogamer, Valve has given the TF-2008 team permission to list the mod on Steam—but did ask that the original idea be altered beforehand. It seems XYK et al happily complied.
"We payed the Steam Direct fee, and are now working on an official Steam release," says XYK on this Facepunch forum. "The Steam team approved of me generating beta CD keys, but we're still waiting on Valve to approve the store page."
XYK follows that with an update: "Valve has gotten back with us, and notified us of some things that needed to be changed. We have done as they recommended, and are now waiting again, on the store page review."
Here's a trailer:
And here's some screens:
Not much else is known about Team Fortress 2008, but you can follow its progress via its Steam page. Again, all going well, it's due January 11, 2019.