diff --git a/cmd/gh-md-toc/main.go b/cmd/gh-md-toc/main.go
index 8a0d205..ca96885 100644
--- a/cmd/gh-md-toc/main.go
+++ b/cmd/gh-md-toc/main.go
@@ -23,6 +23,7 @@ var (
 	indent     = kingpin.Flag("indent", "Indent space of generated list").Default("2").Int()
 	debug      = kingpin.Flag("debug", "Show debug info").Bool()
 	ghurl      = kingpin.Flag("github-url", "GitHub URL, default=https://api.github.com").String()
+	reVersion  = kingpin.Flag("re-version", "RegExp version, default=0").Default("0").String()
 )
 
 // check if there was an error (and panic if it was)
@@ -41,7 +42,7 @@ func processPaths() {
 
 	for _, p := range *paths {
 		ghdoc := ghtoc.NewGHDoc(p, absPathsInToc, *startDepth, *depth, !*noEscape, *token, *indent, *debug)
-		ghdoc.SetGHURL(*ghurl)
+		ghdoc.SetGHURL(*ghurl).SetReVersion(*reVersion)
 
 		if *serial {
 			ch <- ghdoc.GetToc()
@@ -74,6 +75,7 @@ func processSTDIN() {
 	check(os.WriteFile(file.Name(), bytes, 0644))
 	check(ghtoc.NewGHDoc(file.Name(), false, *startDepth, *depth, !*noEscape, *token, *indent, *debug).
 		SetGHURL(*ghurl).
+		SetReVersion(*reVersion).
 		GetToc().
 		Print(os.Stdout))
 }
diff --git a/ghdoc.go b/ghdoc.go
index c7b1c87..bac99da 100644
--- a/ghdoc.go
+++ b/ghdoc.go
@@ -46,6 +46,7 @@ type GHDoc struct {
 	httpGetter httpGetter
 	httpPoster httpPoster
 	ghURL      string
+	reVersion  string
 }
 
 // NewGHDoc create GHDoc
@@ -64,6 +65,7 @@ func NewGHDoc(Path string, AbsPaths bool, StartDepth int, Depth int, Escape bool
 		httpGetter: internal.HttpGet,
 		httpPoster: internal.HttpPost,
 		ghURL:      "https://api.github.com",
+		reVersion:  "0",
 	}
 }
 
@@ -81,6 +83,12 @@ func (doc *GHDoc) SetGHURL(url string) *GHDoc {
 	return doc
 }
 
+// SetReVersion sets reg exp version
+func (doc *GHDoc) SetReVersion(v string) *GHDoc {
+	doc.reVersion = v
+	return doc
+}
+
 // IsRemoteFile checks if path is for remote file or not
 func (doc *GHDoc) IsRemoteFile() bool {
 	u, err := url.Parse(doc.Path)
@@ -160,16 +168,18 @@ func (doc *GHDoc) GrabToc() *GHToc {
 	// si:
 	// 	- s - let . match \n (single-line mode)
 	//  - i - case-insensitive
-	// re := `(?si)<h(?P<num>[1-6]) id="[^"]+">\s*` +
-	// 	`<a class="heading-link"\s*` +
-	// 	`href="(?P<href>[^"]+)">\s*` +
-	// 	`(?P<name>.*?)<span`
-	re := `(?si)<h(?P<num>[1-6])>\s*` +
-		`<a\s*id="user-content-[^"]*"\s*class="anchor"\s*` +
-		`(aria-hidden="[^"]*"\s*)?` +
-		`(tabindex="[^"]*"\s*)?` +
-		`href="(?P<href>[^"]*)"[^>]*>\s*` +
-		`.*?</a>(?P<name>.*?)</h`
+	re := `(?si)<h(?P<num>[1-6]) id="[^"]+">\s*` +
+		`<a class="heading-link"\s*` +
+		`href="(?P<href>[^"]+)">\s*` +
+		`(?P<name>.*?)<span`
+	if doc.reVersion == "0" {
+		re = `(?si)<h(?P<num>[1-6])>\s*` +
+			`<a\s*id="user-content-[^"]*"\s*class="anchor"\s*` +
+			`(aria-hidden="[^"]*"\s*)?` +
+			`(tabindex="[^"]*"\s*)?` +
+			`href="(?P<href>[^"]*)"[^>]*>\s*` +
+			`.*?</a>(?P<name>.*?)</h`
+	}
 	r := regexp.MustCompile(re)
 	listIndentation := internal.GenerateListIndentation(doc.Indent)