The About page claims that this wiki is running the development version. However, edit pages on this wiki have [Preview] buttons, there are no such buttons on the development version (as pulled from the mercurial repository)…
Tip seems to have been rolled back for some reason. http://devel.sheep.art.pl/devel/hatta-dev/raw-file/d133af1a16a4/hatta.py is one step back from tip and seems to have all the goodies.
Thank you for the bug report, indeed I have accidentally put hatta.py from version 1.0.2 in the -dev repo. I don't know how this could happen. It also seems that I didn't update the stable repo properly… Anyways, now everything is fixed.
Perhaps it would be a good idea to have a __version__ string in the wiki script.
Excellent idea, I will put it into life with no further ado!