diff --git a/src/WebdriverClassicDriver.php b/src/WebdriverClassicDriver.php
index 2d4ba13..61363f1 100644
--- a/src/WebdriverClassicDriver.php
+++ b/src/WebdriverClassicDriver.php
@@ -186,10 +186,10 @@ public function switchToWindow(?string $name = null): void
         $this->getWebDriver()->switchTo()->window((string)$name);
     }
 
-    public function switchToIFrame(?string $name = null): void
+    public function switchToIFrame($name = null): void
     {
         $frameQuery = $name;
-        if ($name && $this->getWebDriver()->isW3cCompliant()) {
+        if ($name && !is_int($name) && $this->getWebDriver()->isW3cCompliant()) {
             try {
                 $frameQuery = $this->getWebDriver()->findElement(WebDriverBy::id($name));
             } catch (NoSuchElementException $e) {