[Suicide Junkie]

First figure out whether the update will destroy your savegame or not.
It sounds like there is a good chance your game will be ok, since the version number change is so small, but you should probably test it out on a backup copy of the game, or ask the author.

Once you are satisfied that your savegame will not be ruined, find or upload the new version of the mod in PBW's mod gallery.
Then, in the admin requests forum on PBW, the host should post a message along the lines as follows:

"Hi,
Would you please upgrade my game 'Baneful Icons of the Foe' to use 'Devnull 1.71'

Thanks."