diff --git a/composer.json b/composer.json
index 89fda24..fdc22c7 100644
--- a/composer.json
+++ b/composer.json
@@ -2,7 +2,7 @@
   "name": "nabeghe/wp-shortcodes",
   "description": "A standalone version of WordPress shortcodes system for use outside WordPress.",
   "type": "library",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "homepage": "https://github.com/nabeghe/wp-shortcodes",
   "license": "GPL-2.0+",
   "autoload": {
diff --git a/src/Shortcodes.php b/src/Shortcodes.php
index e2bee37..40aeaf6 100644
--- a/src/Shortcodes.php
+++ b/src/Shortcodes.php
@@ -57,7 +57,7 @@ class Shortcodes
      *                           itself (`$shortcode_tag`), in that order.
      * @throws ShortcodeException
      */
-    public function add(string $tag, callable $callback): void
+    public function add(string $tag, $callback): void
     {
         if ('' === trim($tag)) {
             throw new ShortcodeException('Invalid shortcode name: Empty name given.');