I think you can get some of the earlier versions
on the official AppCAD download website.
The AppCAD Story
Engineering staff of the Microwave Semiconductor
Division of Hewlett-Packard Co. created AppCAD as
a design help for RF & Microwave ("wireless")
designers. AppCAD was then, and still is, distributed
free of charge as a service to the wireless engineering
community. (The Microwave Semiconductor Division
later merged with a different division of HP, all
of which has since become part of Agilent Technologies.)
AppCAD was originally released in 1990 as version
1.02 (the "Classic" version). Version 1.02 was a
DOS program that was compatible with Windows 3.x.
Although based on the original MS-DOS® version
of RF and Microwave AppCAD "Classic," the current
version of Agilent Technologies' AppCAD runs on
32-bit Windows® operating systems and contains many
new and innovative design programs.
on the AppCAD Classic link.