People such as Richard Woolcock, known as KaVir on the internet, the author of the GodWars codebase, and Michael Siefert, one of the original Diku authors, claim that it still is. This is a controversial claim as Medieva accepts money from donations, which would be a violation of the Diku and Merc licences. Richard Woolcock offers Medievia source files on his web site. He claims he copied them while working on Medievia's code. If these files are genuine, they would prove his claims.
Medievia's owner Michael Krause claims that these allegations are unfounded as the entire MUD has been rewritten completely in version 4, thus making it no longer a derivative.