Ubuntu 20.04 will come with LilyPond 2.20. Older releases are usually not updated after the release and will keep 2.18. Ubuntu 2.20 will probably be released tomorrow.
https://packages.ubuntu.com/focal/lilypond Frescobaldi will be 3.0.0 and not the latest 3.1.2: https://packages.ubuntu.com/focal/frescobaldi Cheers, Joram
