install gtkmm-4.0 in ubuntu 20.04
Why can't I do this with
sudo apt install libgtkmm-4.0-dev
It appears to be available in pkgs.org. I know I can install libgtkmm-3.0-dev using the above so why not 4.0?
Solution 1:
Any Ubuntu release has a fixed set of software available in the repositories. Only one version is available - except web browsers and other critical components - and that version was decided some time before the actual release.
According to https://packages.ubuntu.com/search?keywords=gtkmm the gtkmm version available for Ubuntu 20.04 is 3.24.0-1.