I need version 2.65 for my private tracker since they don't allow any other version. It was hard enough to get them to approve this client, so I'll take what I can get. Where can I find the older versions?

Here are links to v2.65:

Windows 64bit
https://download1.tixati.com/download/tixati-2.65-1.win64-install.exe

Linux 64bit
https://download2.tixati.com/download/tixati-2.65-1.x86_64.rpm

Ubuntu 64bit
https://download2.tixati.com/download/tixati_2.65-1_amd64.deb

Standalone/Manual Binary Install 64bit
https://download2.tixati.com/download/tixati-2.65-1.x86_64.manualinstall.tar.gz

Portable
https://download2.tixati.com/download/tixati-2.65-1.portable.zip

Thank you!

Needed here as well, for the same reason.
Links above are dead.

Join a few Tixati channels and use built-in search. In any case make sure to verify your downloads with "gpg --verify" or find a trusted place that published the hash checksums for the original files.

Literally spoof your user agent, otherwise Tixati is unusable on private trackers.