New for specialist notation

• For consistency with other ancient clefs, five new mensural clefs are available: "mensural-f2", "mensural-f3", "mensural-f4" (same as "mensural-f"), "mensural-f5", "mensural-g1", "mensural-g2" (same as "mensural-g").
• The default time signature and accidental style in a PetrucciStaff context is now the same as in MensuralStaff.
• White mensural ligatures now support some rare ligatures (semibreves alone or in the middle), and allow tweaks to show some non-necessary stems.

  \score {
    \relative {
      \set Score.timing = ##f
      \set Score.measureBarType = #'()
      \override NoteHead.style = #'petrucci
      \override Staff.TimeSignature.style = #'mensural
      \clef "petrucci-c4"
      \[ a1 g f e \]
      \[ a1 g\longa \]
      \[ \tweak left-down-stem ##t a\breve b
         \tweak right-down-stem ##t g\longa \]
      \[ \tweak right-down-stem ##t b\maxima
         \tweak right-up-stem ##t g\longa \]
    }
    \layout {
      \context {
        \Voice
        \remove Ligature_bracket_engraver
        \consists Mensural_ligature_engraver
      }
    }
  }
  

  

• The use of the file gregorian.ly is deprecated. While still distributed for backward compatibility, it should be replaced with a VaticanaScore context together with some manual \layout changes (if necessary): code like

  \include "gregorian.ly"
  
  \score {
    \new VaticanaStaff { ... }
  }
  

  should become

  \new VaticanaScore {
    \new VaticanaStaff { ... }
  }
  
  \layout {
    indent = 0
    ragged-last = ##t
  }
  

• LilyPond’s ‘arabic’ note name language is deprecated. While still working for backward compatibility (if you load hel-arabic.ly), it is recommended to use ‘english’, ‘italiano’, or your preferred note name language instead.
• Defaults for fret labels in fret diagrams have changed.
  • − The default value for fret-label-vertical-offset is set to -0.5, which centers the label in the fret space.
  • − The default number format is now 'custom, with a format string of "~dfr" (resulting in ‘3fr’, for example), instead of 'roman-lower.
• Two new options are available for fret-diagram-details:
  • − string-overhang allows to define the extension of string lines beyond the last fret line, in multiples of fret-distance. Default value 1.
  • − barre-thickness defines the thickness of the barre line, in multiples of dot-radius. Only defined for barre-type=straight. Default value 1.
• The command \autoBeamOff now stops auto-beaming immediately. Previously, its effect was delayed if a beam generated by the auto-beamer engraver was still active.
• It is no longer necessary to switch off auto-beaming while using \crossStaff.
• The \upbow and \downbow signs are now properly inverted if used below a staff. As a consequence, the glyphs scripts.upbow and scripts.downbow have been renamed to scripts.uupbow and scripts.udownbow, respectively, and the new inverted glyphs are named scripts.dupbow and scripts.ddownbow.

  \relative c' {
    f4^\downbow f^\upbow f_\downbow f_\upbow
  }
  

  

• In lyrics aligned to a melody, extender lines can now be added automatically for words ending in a melisma.

  \relative {
    d'4 e f4 g8( f
    e4 d c2)
  }
  \addlyrics {
    \set autoExtenders = ##t
    A me -- lis -- ma.
  }
  

  

• LilyPond now follows the Ignatzek chord name scheme more closely. This reverts changes introduced in version 2.15.21 (in 2011), which are now considered as incorrect and/or ambiguous.

  oldException = { <c e g b fis'>-\markup \super "lyd" }
  chExceptions = #(append (sequential-music-to-chord-exceptions
                           oldException #t)
                          ignatzekExceptions)
  
  music = { <c e g d'>1 | <c es g f'> | <c e g b fis'> }
  
  \new StaffGroup \with { instrumentName = "old:" }
  <<
    \new ChordNames \with {
      chordNameExceptions = #chExceptions
      additionalPitchPrefix = ""
    } \music
    \new Voice \transpose c c' \music
  >>
  
  \new StaffGroup \with { instrumentName = "new:" }
  <<
    \new ChordNames \music
    \new Voice \transpose c c' \music
  >>
  
  \layout {
    indent = 1\cm
    line-width = 9\cm
    ragged-right = ##f
  }