diff --git a/composer.json b/composer.json
index b0db660..95ebd7b 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
     ],
     "require": {
         "php": ">=5.3",
-        "ezyang/htmlpurifier": "^4.8"
+        "ezyang/htmlpurifier": "^4.19"
     },
     "require-dev": {
         "phpunit/phpunit": ">=4.7 <10.0",
diff --git a/library/HTMLPurifier/Lexer/HTML5.php b/library/HTMLPurifier/Lexer/HTML5.php
index a558040..50fe18d 100644
--- a/library/HTMLPurifier/Lexer/HTML5.php
+++ b/library/HTMLPurifier/Lexer/HTML5.php
@@ -57,16 +57,7 @@ public function tokenizeHTML($html, $config, $context)
     protected function armor($html, HTMLPurifier_Config $config)
     {
         if ($config->get('Core.AggressivelyFixLt')) {
-            $char = '[^a-z!\/]';
-            $comment = "/<!--(.*?)(-->|\z)/is";
-            $html = preg_replace_callback($comment, array($this, 'callbackArmorCommentEntities'), $html);
-
-            do {
-                $old = $html;
-                $html = preg_replace("/<($char)/i", '&lt;\\1', $html);
-            } while ($html !== $old);
-
-            $html = preg_replace_callback($comment, array($this, 'callbackUndoCommentSubst'), $html); // fix comments
+            $html = $this->aggressivelyFixLt($html);
         }
 
         return $html;