use lilypond 2.27 and be compatibel to 2.26

private_includes/base/chordpro.ily

@@ -319,14 +319,21 @@
                  ;; Use context property if available, otherwise grob property
                  (stanza-markup (or stanza-text-from-context stanza-text-from-grob))
                  ;; For ref/bridge, always use format-chordpro-stanza-label
-                 ;; For verse, extract from markup (includes roman numerals if \romanStanza was used)
-                 (stanza-text (if (or (eq? stanza-type 'ref) (eq? stanza-type 'bridge))
-                                 (format-chordpro-stanza-label stanza-type stanza-numbers)
+                 ;; For verses set by \fstanza, format the numbers (roman numerals if \romanStanza was used)
+                 ;; Otherwise, extract from markup
+                 (stanza-text (cond
+                               ((or (eq? stanza-type 'ref) (eq? stanza-type 'bridge))
+                                 (format-chordpro-stanza-label stanza-type stanza-numbers))
+                               (custom-realstanza
+                                 (format-stanza-numbers
+                                   (ly:assoc-get 'custom-stanzanumber-override details stanza-numbers)
+                                   (ly:grob-property grob 'style #f)))
+                               (else
                                  (if (markup? stanza-markup)
                                      (markup->string stanza-markup)
                                      (if stanza-markup
                                          (format #f "~a" stanza-markup)
-                                         #f))))
+                                         #f)))))
                  (existing (assoc this-verse-index chordpro-stanza-numbers))
                  (moment (ly:context-current-moment (ly:translator-context source-engraver)))
                  (direction (ly:grob-property grob 'direction CENTER)))