I am on zorin 17.3 core
Ubuntu.
Zorin OS is based on Ubuntu, so most things you do, you can just consider applying an Ubuntu (or sometimes, Debian, upon which Ubuntu is based) solution.
Ubuntu is flavor based.
(e.g. Kubuntu, Xubuntu...)
It also has versions.
(Xenial, Bionic, Focal... These are codenames.)
So... Zorin OS 17 is based on Ubuntu 22.04.
Zorin OS 18 is based on Ubuntu 24.04
In a drop down selection like this - select "Ubuntu" - also true if talking to a Vendors Tech Support.
For your package management, keep all sources to be your Zorin Ubuntu Base
Zorin OS 17 - all sources should point to Jammy
Zorin OS 18 - All sources should point to Noble
Ubuntu 22.04 Zorin 17 is based on is named Jammy. Your sources should come from Jammy.
Focal is the name for ubuntu 20.04 Zorin 16 was based on.
Thanks for the save - My brain froze.
