The update adds contextual menus in Mac OS X to version 6.5's Magic Menu implementation. It also adds smart expansion of Palm OS files.
StuffIt Lite and StuffIt Deluxe 6.5 users should update for minor bug fixes and the new StuffIt Deluxe-Only Mac OS X Context Menu feature.
StuffIt group product manager, Peter Thomas, said: "Our Mac OS X users are thrilled to have this support and we're happy to be able to provide it for free."
Owners of StuffIt Deluxe 6.0 who bought the software after October 12 and have retained proof of purchase can upgrade to StuffIt Deluxe 6.5.1 for free. Registered owners of any previous version of StuffIt Deluxe, DropStuff and DropZip can upgrade to StuffIt Deluxe 6.5.1 for $19.95 until January 31. UK pricing for the upgrade is unavailable.
StuffIt Deluxe has a street price of £75 (ex VAT).