As of the next reboot, your "change xml" mode is no longer saved on your
character, but has to be enabled every time you start a new session.
Also, there is a special client command that lets you turn it on or off. If you
know how the MUME client protocol works, this should make sense:
MPI X 1 \n 1
Replace the last '1' with 0 to turn off.
The idea is that an XML-aware client that connects to MUME should send that
command to enable XML mode as soon as possible.