This page attempts to answer questions regarding the plugin which I receive most frequently.
If all TTT commands return the message /ttt [subcommand], you probably installed the plugin incorrectly. Verify that the latest version of Steel is installed on the server. If so, check for startup errors which mention TTT and create an issue, including the startup error with it (preferably through a service like Pastebin or Gist).
See the issue tracker, which has all currently planned features along with their respective milestones. If an issue doesn't have a milestone attached, that generally means it's planned for a far-future version.
Also, note that while I try to avoid deferring issues once they've been assigned to a milestone, it does occasionally happen to allow me to get other features into release more quickly, so these goals are not necessarily set in stone.
Because I work on TTT in my spare time, it's tough to give a concrete ETA on when the next version will be ready. I currently expect to have version 0.12 ready by March April ??? of 2017 ??? (though this is highly subject to change).
I'll be honest, I may abandon this project. I'm currently debating finishing up a couple more long-standing feature requests before that happens. I'll keep this space updated on that.
I can't say. I only really have a reliable ETA for the immediate next version.
Check the BukkitDev project for Bukkit versions supported by each version of TTT. Most notably, v0.11 dropped support for Bukkit 1.7.x, and v0.12 will drop support for everything older than Bukkit 1.8.8.
Note that while older versions are officially supported, you may experience bugs since I primarily test on the latest Minecraft version. If you experience bugs on an officially supported version, please create an issue so I can fix it.