It seems like Multi Server on windows has become abandon-ware. The linux client, shaky to begin with, hasn't been updated for over two years and is a bit of a struggle to wedge onto modern distributions. The windows client is almost as dusty and problematic. The server software itself eats its config files, throws asserts and corrupts catalogs with frightening regularity.
I'm wondering what other multi platform backup systems people are looking at that support Windows (Desktop and server), MacOS and Linux.