You can upgrade from 1.2.0 to 1.2.1 either through the network or with
the 1.2.1 CD-ROM.

For network upgrades make sure you have this line:

   deb http://demudi.agnula.org/packages/demudi stable main

in  your  /etc/apt/sources.list and  that  you  are  connected to  the
Internet.

For  CD-ROM upgrades  insert the  1.2.1 CD-ROM  in the  tray,  the run
apt-cdrom add.

Now update the demudi package:

   apt-get update
   apt-get install demudi

Some packages will be remove, just answer "Yes", it's allright.

Finally run:

   apt-get dist-upgrade

The procedure is not yet fully tested. Please report any problems to
the AGNULA mailing lists.