Comment 73 for bug 2055114

@brian-murray the wiki mentioned to add proposed is sadly outdated and for 16.04. More recent documents, show this changed radically in 24.04 so that you can cherry pick updates you want, starting with add-apt-repository -yp proposed. This didn't work for me neither.

I did as follows:

- Open /etc/apt/sources.list.d/ubuntu.sources and add noble-proposed
- apt update
- apt-get install -t noble-proposed fail2ban
- fail2ban now works again
- Open /etc/apt/sources.list.d/ubuntu.sources and remove noble-proposed
- apt update

You are now safe to not accidently update other packages from proposed if that's not wanted (ie. on a production system).

Hope this helps someone. It works for me and I can confirm that fail2ban is working again with this approach.