MacUpdate 3 is a File Synchronization and Folder Reconciliation
program for the Macintosh. System 6 and System 7 are both OK.
MacUpdate 3 is useful for doing incremental backups, as well as for
keeping two (or more) directories on two (or more) Macintoshes up-to-
date with each other.

MacUpdate 3 works well with any HFS volume that can be mounted on the
Macintosh "Desktop". This includes Hard Disks and Partitions,
Floppies, SyQuest Drives, Opticals, and AppleShare & EtherNet volumes.

See also: [MacUpdate 4.x][1]

Compatibility
Architecture: 68k

System 6 or later

  [1]: http://macintoshgarden.org/apps/macupdate-4x