To update DVD Catalyst 3 to the latest version, all that needs to be done is to click on the (big) cat-eyes on the top left in the program.

This will have DVD Catalyst 3 connect to the www.tools4movies.com website, and check for the latest version. If the version on the website is different from the one you are using, it will offer to download the update.
Once the update is downloaded, just install it.

Because the update is not a full DVD Catalyst installer (the update is only 1mb, while the full installer is about 10mb) you should not uninstall DVD Catalyst 3 to install the update.

Because DVD Catalyst 3 does not use license keys (personal reasons) installing a (newer) trial version will not update DVD Catalyst 3 to a retail version. It will make it into a trial version, and you will have to use your original link to download the full version again.

For DVD Catalyst 2 users, the update process no longer works.

Because the dvdcatalyst.com domain has been STOLEN, the update process connects to a website we no longer have access to. 2.7 is the last DVD Catalyst 2 version.