How to obtain old version of the linux editor?

I have a project build on 2018.3.10f1 that needs to be built and run on linux as part of a project integrated with a good deal of linux-specific software. Upgrading it to lts 2018.4 version broke a lot of stuff, but I can't seem to find a way to download the old linux versions. The release notes blog posts all have windows/mac downloads, and so do does the "old version" page on the website.

I found this unity hub link: unityhub://2018.3.10f1/f88de2c96e63, but unity hub does not seem to do anything when I click this in firefox on ubuntu 18. Any tips for getting this old version downloaded?