Old Versions available?

Why would I want an old version of AuthPass?
Well, because I have an old version of an operating system on an old machine that will not allow any further upgrades.
So I want to download an installer file of a previous version of AuthPass that will work on an iMac 8,1 (Early 2008) running Mac OS X 10.10 Yosemite.
Can anyone help please?