The demo version of the Team Fortress 2 Classic modification was expected to be released on Steam in October. However, an unpleasant detail emerged during the process, which neither the developers nor Valve moderators noticed.
It turns out that on Steam, an application cannot be both a modification and a demo version at the same time, so the demo launch was canceled:
«During the final stages of the review process, we were informed that an application on Steam cannot be both a mod and a demo at the same time. Unfortunately, no one at EMINOMA or Valve noticed this until last Saturday, as the initial reviews did not flag this as an issue and gave us the mistaken impression that we could release the game.»
The release of the Team Fortress 2 Classic mod itself on Steam is still planned, the page is available at the following link.