2 Updating files with convert-ly

As LilyPond is improved, the syntax (input language) of some commands and functions can change. This usually results in unexpected errors, warnings, or even wrong output when input files, previously created for older versions of LilyPond, are then used with later versions.

To help with this, the convert-ly command can be used to upgrade older input files to the newer syntax.

LilyPond Application Usage v2.25.18 (development-branch).