RTPatch
From Just Solve the File Format Problem
RTPatch is a proprietary commercial software-updating system produced by Pocket Soft since 1991. They produce client and server software for sending and applying updates to software systems, including the generation of diff files encompassing changes. Some aspects of their system are patented.
RTPatch Professional had the ability to create self-extracting executables using something called SELFEX Version 3.20 Maybe other versions exist.
