according to the release notes this update offers disc spanning for backing up large files that won't fit on a single disc, scanning performance improvements, combined CD and DVD modes, an updated iTunes QuickPick, iCal and Stickies QuickPicks, improved log files, support for different sizes of recordable discs, and an updated design with a brushed-metal look, Backup 1.2.1 requires Jag.
http://www.mac.com/WebObjects/Tools.woa/5/wo/6qouOS77TgtKNmoh.1/2.0.11.3.27.22.26.4 or use the software updater.
http://www.mac.com/WebObjects/Tools.woa/5/wo/6qouOS77TgtKNmoh.1/2.0.11.3.27.22.26.4 or use the software updater.