Have you checked the page:
Downloads then scroll down to the software you have and click on it?
One thing I do is create a file folder with all of the downloaded zip files. Sometimes I have to rename them with a date to keep track of them.
Every now and then I'll find the previous version works a little better than the latest. Retaining all the downloads helps me to work backwards if needed.
I'll also put the software keys in a word processing file, saving them in the same folder as the downloaded zip files. It helps to retrieve the keys via copy and paste. Each time a new version is downloaded it must be registered, so you'll need to have the registration keys handy.