-The following is a fundamental change in LilyPond's music
-representation: Rhythmic events like @code{LyricEvent} and
-@code{NoteEvent} are no longer wrapped in @code{EventChord} unless they
-have been actually entered as part of a chord in the input. If you
-manipulate music expressions in Scheme, the new behavior may require
-changes in your code. The advantages of making input and music match
-more closely are numerous: music functions previously worked differently
-when used inside or outside of chords. Now they are the same, including
-all the possibilities of argument parsing. You can now use music
-variables inside of chords: a construct like
-@lilypond[verbatim,quote,ragged-right]
-tonic=fis'
-{ <\tonic \transpose c g \tonic> }
-@end lilypond
-@noindent
-would have been unthinkable previously. You can use
-@code{#@{@dots{}#@}} for constructing chord constituents. Music
-functions inside of chords are no longer specially treated and thus
-accept the same arguments as outside of chords. @code{\tweak} now works
-on single notes without needing to wrap them in a chord. In theory, it
-can also work on command events and lyrics now. Since that was not
-possible before, it depends on luck on a case-by-case basis whether the
-tweak internals are already receiving the necessary information. Users
-are asked to report those cases where they find @code{\tweak} not
-working according to reasonable expectations.
+When @code{\relative} is used without an explicit reference pitch,
+the reference pitch now is the middle of the first octave, making
+the first entered pitch indistinguishable from absolute pitch.
+Previously, omitting the reference pitch would have lead to a
+default of @code{c'}. Since that choice was somewhat arbitrary,
+recommended usage was to always specify the reference pitch.