diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index cc04c59..0688575 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 9.1.  Last change: 2024 Apr 09
+*syntax.txt*	For Vim version 9.1.  Last change: 2024 Apr 13
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -3764,12 +3764,15 @@
    g:vimsyn_folding == 0 or doesn't exist: no syntax-based folding
    g:vimsyn_folding =~ 'a' : augroups
    g:vimsyn_folding =~ 'f' : fold functions
+   g:vimsyn_folding =~ 'h' : fold heredocs
+   g:vimsyn_folding =~ 'H' : fold Vim9-script legacy headers
    g:vimsyn_folding =~ 'l' : fold lua      script
    g:vimsyn_folding =~ 'm' : fold mzscheme script
    g:vimsyn_folding =~ 'p' : fold perl     script
    g:vimsyn_folding =~ 'P' : fold python   script
    g:vimsyn_folding =~ 'r' : fold ruby     script
    g:vimsyn_folding =~ 't' : fold tcl      script
+let g:vimsyn_folding = 'acfhlmpPrt'
 <
 							*g:vimsyn_noerror*
 Not all error highlighting that syntax/vim.vim does may be correct; Vim script
diff --git a/runtime/syntax/generator/vim.vim.base b/runtime/syntax/generator/vim.vim.base
index 7c6a9a0..f5e2110 100644
--- a/runtime/syntax/generator/vim.vim.base
+++ b/runtime/syntax/generator/vim.vim.base
@@ -3,7 +3,7 @@
 " Maintainer:	   Hirohito Higashi <h.east.727 ATMARK gmail.com>
 "	   Doug Kearns <dougkearns@gmail.com>
 " URL:	   https://github.com/vim-jp/syntax-vim-ex
-" Last Change:	   2024 Apr 09
+" Last Change:	   2024 Apr 12
 " Former Maintainer: Charles E. Campbell
 
 " DO NOT CHANGE DIRECTLY.
@@ -79,7 +79,7 @@
 " Special Vim Highlighting (not automatic) {{{1
 
 " Set up folding commands for this syntax highlighting file {{{2
-if exists("g:vimsyn_folding") && g:vimsyn_folding =~# '[afhlmpPrt]'
+if exists("g:vimsyn_folding") && g:vimsyn_folding =~# '[afhHlmpPrt]'
  if g:vimsyn_folding =~# 'a'
   com! -nargs=* VimFolda <args> fold
  else
@@ -95,6 +95,11 @@
  else
   com! -nargs=* VimFoldh <args>
  endif
+ if g:vimsyn_folding =~# 'H'
+  com! -nargs=* VimFoldH <args> fold
+ else
+  com! -nargs=* VimFoldH <args>
+ endif
  if g:vimsyn_folding =~# 'l'
   com! -nargs=* VimFoldl <args> fold
  else
@@ -129,6 +134,7 @@
  com! -nargs=*	VimFolda	<args>
  com! -nargs=*	VimFoldf	<args>
  com! -nargs=*	VimFoldh	<args>
+ com! -nargs=*	VimFoldH	<args>
  com! -nargs=*	VimFoldl	<args>
  com! -nargs=*	VimFoldm	<args>
  com! -nargs=*	VimFoldp	<args>
@@ -827,11 +833,11 @@
 " ==================
 
 if s:vim9script
-  syn cluster vimLegacyTop contains=TOP,vimPreVim9script,vim9Comment,vim9LineComment
-  syn region vimPreVim9script start="\%^" end="^\ze\s*vim9s\%[cript]\>" contains=@vimLegacyTop,vimComment,vimLineComment
+  syn cluster vimLegacyTop	contains=TOP,vim9LegacyHeader,vim9Comment,vim9LineComment
+  VimFoldH syn region vim9LegacyHeader start="\%^" end="^\ze\s*vim9s\%[cript]\>" contains=@vimLegacyTop,vimComment,vimLineComment
 
-  syn keyword vim9ScriptArg noclear
-  syn keyword vimCommand vim9s[cript] nextgroup=vim9ScriptArg skipwhite
+  syn keyword vim9Vim9ScriptArg	noclear contained
+  syn keyword vim9Vim9Script	vim9s[cript] nextgroup=vim9Vim9ScriptArg skipwhite
 endif
 
 " Embedded Scripts:  {{{2
@@ -1041,7 +1047,7 @@
   hi def link vimBufnrWarn	vimWarn
  endif
 
- hi def link vim9ScriptArg	Special
+ hi def link vim9Vim9ScriptArg	Special
  hi def link vimAbb	vimCommand
  hi def link vimAddress	vimMark
  hi def link vimAugroupBang	vimBang
@@ -1171,6 +1177,7 @@
  hi def link vimSetMod	vimOption
  hi def link vimSetSep	Statement
  hi def link vimSetString	vimString
+ hi def link vim9Vim9Script	vimCommand
  hi def link vimSpecFile	Identifier
  hi def link vimSpecFileMod	vimSpecFile
  hi def link vimSpecial	Type
@@ -1235,6 +1242,8 @@
 " Cleanup: {{{1
 delc VimFolda
 delc VimFoldf
+delc VimFoldh
+delc VimFoldH
 delc VimFoldl
 delc VimFoldm
 delc VimFoldp
diff --git a/runtime/syntax/testdir/dumps/vim9_legacy_header_fold_00.dump b/runtime/syntax/testdir/dumps/vim9_legacy_header_fold_00.dump
new file mode 100644
index 0000000..b324c46
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim9_legacy_header_fold_00.dump
@@ -0,0 +1,20 @@
+>++0#0000e05#a8a8a8255|-@1| |1@1| |l|i|n|e|s|:| |"| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |l|e|t| |g|:|v|i|m|s|y|n|_|f|o|l|d|i|n|g| |=| |"|H|"| ||| |s|e|t| |f|d|m|=|s|y|n|t|a|x|-
+|v+0#af5f00255#ffffff0|i|m|9|s|c|r|i|p|t| +0#0000000&|n+0#e000e06&|o|c|l|e|a|r| +0#0000000&@56
+@75
+|#+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@65
+@75
+| +0#0000e05&|#| |s|t|r|i|n|g| |o|n|l|y| |r|e|c|o|g|n|i|s|e|d| |w|i|t|h| |l|e|a|d|i|n|g| |c|h|a|r| +0#0000000&@31
+@1|"+0#e000002&|u|s|e|l|e|s@1| |s|t|r|i|n|g|"| +0#0000000&@57
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1| 
diff --git a/runtime/syntax/testdir/dumps/vim9_legacy_header_fold_99.dump b/runtime/syntax/testdir/dumps/vim9_legacy_header_fold_99.dump
new file mode 100644
index 0000000..b3fa847
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/vim9_legacy_header_fold_99.dump
@@ -0,0 +1,20 @@
+|++0#0000e05#a8a8a8255|-@1| |1@1| |l|i|n|e|s|:| |"| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |l|e|t| |g|:|v|i|m|s|y|n|_|f|o|l|d|i|n|g| |=| |"|H|"| ||| |s|e|t| |f|d|m|=|s|y|n|t|a|x|-
+|v+0#af5f00255#ffffff0|i|m|9|s|c|r|i|p|t| +0#0000000&|n+0#e000e06&|o|c|l|e|a|r| +0#0000000&@56
+@75
+|#+0#0000e05&| |c|o|m@1|e|n|t| +0#0000000&@65
+@75
+| +0#0000e05&|#| |s|t|r|i|n|g| |o|n|l|y| |r|e|c|o|g|n|i|s|e|d| |w|i|t|h| |l|e|a|d|i|n|g| |c|h|a|r| +0#0000000&@31
+@1>"+0#e000002&|u|s|e|l|e|s@1| |s|t|r|i|n|g|"| +0#0000000&@57
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|7|,|2| @9|A|l@1| 
diff --git a/runtime/syntax/testdir/input/vim9_legacy_header_fold.vim b/runtime/syntax/testdir/input/vim9_legacy_header_fold.vim
new file mode 100644
index 0000000..6e0e71e
--- /dev/null
+++ b/runtime/syntax/testdir/input/vim9_legacy_header_fold.vim
@@ -0,0 +1,17 @@
+" VIM_TEST_SETUP let g:vimsyn_folding = "H" | set fdm=syntax
+" comment
+
+if !has('vim9script')
+  # 42 " comment
+  source foo.vim
+  finish
+endif
+
+" comment
+
+vim9script noclear
+
+# comment
+
+ # string only recognised with leading char
+ "useless string"
diff --git a/runtime/syntax/vim.vim b/runtime/syntax/vim.vim
index c016703..c5f6b69 100644
--- a/runtime/syntax/vim.vim
+++ b/runtime/syntax/vim.vim
@@ -3,7 +3,7 @@
 " Maintainer:	   Hirohito Higashi <h.east.727 ATMARK gmail.com>
 "	   Doug Kearns <dougkearns@gmail.com>
 " URL:	   https://github.com/vim-jp/syntax-vim-ex
-" Last Change:	   2024 Apr 11
+" Last Change:	   2024 Apr 13
 " Former Maintainer: Charles E. Campbell
 
 " DO NOT CHANGE DIRECTLY.
@@ -116,7 +116,7 @@
 " Special Vim Highlighting (not automatic) {{{1
 
 " Set up folding commands for this syntax highlighting file {{{2
-if exists("g:vimsyn_folding") && g:vimsyn_folding =~# '[afhlmpPrt]'
+if exists("g:vimsyn_folding") && g:vimsyn_folding =~# '[afhHlmpPrt]'
  if g:vimsyn_folding =~# 'a'
   com! -nargs=* VimFolda <args> fold
  else
@@ -132,6 +132,11 @@
  else
   com! -nargs=* VimFoldh <args>
  endif
+ if g:vimsyn_folding =~# 'H'
+  com! -nargs=* VimFoldH <args> fold
+ else
+  com! -nargs=* VimFoldH <args>
+ endif
  if g:vimsyn_folding =~# 'l'
   com! -nargs=* VimFoldl <args> fold
  else
@@ -166,6 +171,7 @@
  com! -nargs=*	VimFolda	<args>
  com! -nargs=*	VimFoldf	<args>
  com! -nargs=*	VimFoldh	<args>
+ com! -nargs=*	VimFoldH	<args>
  com! -nargs=*	VimFoldl	<args>
  com! -nargs=*	VimFoldm	<args>
  com! -nargs=*	VimFoldp	<args>
@@ -871,11 +877,11 @@
 " ==================
 
 if s:vim9script
-  syn cluster vimLegacyTop contains=TOP,vimPreVim9script,vim9Comment,vim9LineComment
-  syn region vimPreVim9script start="\%^" end="^\ze\s*vim9s\%[cript]\>" contains=@vimLegacyTop,vimComment,vimLineComment
+  syn cluster vimLegacyTop	contains=TOP,vim9LegacyHeader,vim9Comment,vim9LineComment
+  VimFoldH syn region vim9LegacyHeader start="\%^" end="^\ze\s*vim9s\%[cript]\>" contains=@vimLegacyTop,vimComment,vimLineComment
 
-  syn keyword vim9ScriptArg noclear
-  syn keyword vimCommand vim9s[cript] nextgroup=vim9ScriptArg skipwhite
+  syn keyword vim9Vim9ScriptArg	noclear contained
+  syn keyword vim9Vim9Script	vim9s[cript] nextgroup=vim9Vim9ScriptArg skipwhite
 endif
 
 " Embedded Scripts:  {{{2
@@ -1085,7 +1091,7 @@
   hi def link vimBufnrWarn	vimWarn
  endif
 
- hi def link vim9ScriptArg	Special
+ hi def link vim9Vim9ScriptArg	Special
  hi def link vimAbb	vimCommand
  hi def link vimAddress	vimMark
  hi def link vimAugroupBang	vimBang
@@ -1215,6 +1221,7 @@
  hi def link vimSetMod	vimOption
  hi def link vimSetSep	Statement
  hi def link vimSetString	vimString
+ hi def link vim9Vim9Script	vimCommand
  hi def link vimSpecFile	Identifier
  hi def link vimSpecFileMod	vimSpecFile
  hi def link vimSpecial	Type
@@ -1279,6 +1286,8 @@
 " Cleanup: {{{1
 delc VimFolda
 delc VimFoldf
+delc VimFoldh
+delc VimFoldH
 delc VimFoldl
 delc VimFoldm
 delc VimFoldp