Aladdin Systems has released StuffIt Deluxe 6.0 with ReturnReceipt technology, which tells users when an email recipient has uncompressed an attachment.
Supporting the Mac OS X Public Beta, StuffIt Deluxe 6.0 includes ArchiveSearch, which finds compressed files by name, date, kind and size.
Peter Thomas, StuffIt product manager, said: "In business today, how many times do we ask, did you get my email with the attachment? With ReturnReceipt technology integrated into StuffIt Deluxe 6.0, users can relax knowing that their compressed files have been successfully opened."
Customers who purchased StuffIt Deluxe 5.5.x in October 2000 or later are entitled to a free upgrade.
The utility costs £55. For a limited period, registered users of earlier versions of StuffIt Deluxe, DropStuff, DropZip and StuffIt Lite can upgrade to StuffIt for $29.95, no UK upgrade price is available yet.