Other SE posts, for example this, show how you can install a specific package version. However, I'm unsure what exactly the naming convention / syntax used for the version I want is.
I need to install rdiff-backup version 1.2.8, but I'm unclear from looking through github (I'm a noob) what the full package version would be called.
Edit: I should note that I did try the syntax of,
sudo apt-get install rdiff-backup=1.2.8
as well as
sudo apt-get install rdiff-backup=1.2.8-1ubuntu1 \
(the latter just blindly copying the syntax shown in the linked example, in the off chance it worked.)
And as the title states, the commands I've looked up that people say should list all or old versions of packages don't seem to work as intended (or as I understand them).
Thanks for your time.