2.6 Manual conversions
In theory, a program like convert-ly could handle any
syntax change. After all, a computer program interprets the old
version and the new version, so another computer program can
translate one file into another.3
However, the LilyPond project has limited resources: not all
conversions are performed automatically. If convert-ly
is not able to handle a syntax change, it emits a warnings like
the following (from the 2.23.12 conversion rule).
Not smart enough to convert music following \fine. Warning: \fine no longer enforces the end of the music. If your piece has music following \fine that you want to exclude when it is unfolded, use \volta to exclude it. Please refer to the manual for details, and update manually.
Footnotes
(3)
At least, this is possible in any LilyPond file that does not contain Scheme code. Otherwise the LilyPond file contains a Turing-complete language, and we run into problems with the famous “Halting Problem” in computer science.