Anacronia's engine, Av4, is written in modern Perl and is being actively developed.
Check the features page for a list of the MUD engine features, or delve right in the code.
The latest development revision of the server can be found -- when running -- at server.mud.it:5000.
For any questions, do not hesitate to e-mail me at either of the two addresses shown on the Ubuntu keyserver page linked to in the footer of every page on this website.