diff --git a/src/ReCaptcha/RequestMethod/SocketPost.php b/src/ReCaptcha/RequestMethod/SocketPost.php
index c45d744..955a49d 100644
--- a/src/ReCaptcha/RequestMethod/SocketPost.php
+++ b/src/ReCaptcha/RequestMethod/SocketPost.php
@@ -107,7 +107,7 @@ public function submit(RequestParameters $params): string
             $response = '';
         }
 
-        if (0 !== strpos($response, 'HTTP/1.0 200 OK')) {
+        if (1 !== preg_match('#^HTTP/1\.[01] 200 OK#', $response)) {
             return '{"success": false, "error-codes": ["'.ReCaptcha::E_BAD_RESPONSE.'"]}';
         }
 
diff --git a/tests/ReCaptcha/RequestMethod/SocketPostTest.php b/tests/ReCaptcha/RequestMethod/SocketPostTest.php
index ef45a78..ec6193e 100644
--- a/tests/ReCaptcha/RequestMethod/SocketPostTest.php
+++ b/tests/ReCaptcha/RequestMethod/SocketPostTest.php
@@ -182,6 +182,22 @@ public function testOverrideSiteVerifyUrl(): void
         $this->assertTrue(SocketPostGlobalState::$fcloseCalled);
     }
 
+    public function testSubmitReturnsResponseWhenHttp11(): void
+    {
+        SocketPostGlobalState::$fgetsResponses = [
+            "HTTP/1.1 200 OK\r\n",
+            "Content-Type: application/json\r\n",
+            "\r\n",
+            'RESPONSEBODY',
+        ];
+
+        $sp = new SocketPost();
+        $response = $sp->submit(new RequestParameters('secret', 'response'));
+
+        $this->assertEquals('RESPONSEBODY', $response);
+        $this->assertTrue(SocketPostGlobalState::$fcloseCalled);
+    }
+
     public function testStreamTimeoutFailureReturnsError(): void
     {
         SocketPostGlobalState::$streamSetTimeoutSuccess = false;
@@ -272,4 +288,33 @@ public function testStreamGetContentsReturnsFalse(): void
 
         $this->assertEquals('{"success": false, "error-codes": ["'.ReCaptcha::E_BAD_RESPONSE.'"]}', $response);
     }
+
+    public function testBadResponseReturnsErrorWhenHttp11(): void
+    {
+        SocketPostGlobalState::$fgetsResponses = [
+            "HTTP/1.1 500 Internal Server Error\r\n",
+            "\r\n",
+            'FAIL',
+        ];
+
+        $sp = new SocketPost();
+        $response = $sp->submit(new RequestParameters('secret', 'response'));
+
+        $this->assertEquals('{"success": false, "error-codes": ["'.ReCaptcha::E_BAD_RESPONSE.'"]}', $response);
+    }
+
+    public function testBadResponseReturnsErrorWhenHttp2(): void
+    {
+        SocketPostGlobalState::$fgetsResponses = [
+            "HTTP/2.0 200 OK\r\n",
+            "Content-Type: application/json\r\n",
+            "\r\n",
+            'RESPONSEBODY',
+        ];
+
+        $sp = new SocketPost();
+        $response = $sp->submit(new RequestParameters('secret', 'response'));
+
+        $this->assertEquals('{"success": false, "error-codes": ["'.ReCaptcha::E_BAD_RESPONSE.'"]}', $response);
+    }
 }