I've encountered a user who alleges that 25.0.1364.160 is the latest version, so I guess that she is still using Ubuntu Lucid (10.04), because chromium-browser is up-to-date in later releases.
To get a recent version, I tried to add the 14.04 LTS repository, and pinned chromium-browser:
sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu trusty universe"
cat <<HEREDOC | sudo tee /etc/apt/preferences.d/chromium-browser-pin-400
Package: *
Pin: release n=trusty
Pin-Priority: 400
Package: chromium-browser chromium-browser-l10n chromium-codecs-ffmpeg chromium-codecs-ffmpeg-extra
Pin: release n=trusty
Pin-Priority: 500
HEREDOC
sudo apt-get update
sudo apt-get upgrade
I don't have Lucid at hand, so I tested the previous in a 11.10 live CD that I still had lingering around. Unfortunately, installation failed because of unmet dependencies. Before diving even deeper into resolving unmet dependencies, I want to know whether this way of getting the latest chromium-browser is viable.
If not: what is the recommended way of installing the latest stable version of Chromium on an old Ubuntu version?