diff --git a/helpers/html_helper.php b/helpers/html_helper.php
index 3e56479..c44b374 100644
--- a/helpers/html_helper.php
+++ b/helpers/html_helper.php
@@ -256,7 +256,7 @@ function html_tag($tag, $attr = array(), $content = false)
         $html .= (!empty($attr)) ? ' ' . (is_array($attr) ? arrayToAttributes($attr) : $attr) : '';
 
         // a void element?
-        if (in_array(mb_strtolower($tag), $void_elements)) {
+        if (in_array(mb_strtolower((string) $tag), $void_elements)) {
             // these can not have content
             $html .= ' />';
         } else {
diff --git a/helpers/request_helper.php b/helpers/request_helper.php
index 9aaed99..d0d67bd 100644
--- a/helpers/request_helper.php
+++ b/helpers/request_helper.php
@@ -23,7 +23,7 @@
      */
     function sendSimpleGetRequest($url = '', $data = array(), $method = 'GET')
     {
-        $method = mb_strtoupper($method);
+        $method = mb_strtoupper((string)$method);
         if ((!empty($data) && (is_array($data) || is_object($data)))) {
             $target = $url . '?' . http_build_query($data);
         } else {
@@ -39,7 +39,7 @@ function sendSimpleGetRequest($url = '', $data = array(), $method = 'GET')
             CURLOPT_MAXREDIRS => 10,
             CURLOPT_TIMEOUT => 30,
             CURLOPT_FOLLOWLOCATION => true,
-            CURLOPT_CUSTOMREQUEST => "GET",
+            CURLOPT_CUSTOMREQUEST => $method,
             CURLOPT_HTTPHEADER => array($UA),
         );
         if (isset($parseUrl['scheme']) && $parseUrl['scheme'] === 'https') {
diff --git a/helpers/string_helper.php b/helpers/string_helper.php
index 51356d1..e8c625e 100644
--- a/helpers/string_helper.php
+++ b/helpers/string_helper.php
@@ -473,10 +473,10 @@ function str_starts_with($needle, $haystack)
      */
     function str_ignore_starts_with($needle, $haystack)
     {
-        $hs = mb_strtolower($haystack);
+        $hs = mb_strtolower((string) $haystack);
 
         foreach ((array)$needle as $ndl) {
-            $n = mb_strtolower($ndl);
+            $n = mb_strtolower((string) $ndl);
             if ($n !== '' && mb_strpos($hs, $n) === 0) {
                 return true;
             }
@@ -568,10 +568,10 @@ function str_ends_with($needle, $haystack)
      */
     function str_ignore_ends_with($needle, $haystack)
     {
-        $hs = mb_strtolower($haystack);
+        $hs = mb_strtolower((string) $haystack);
 
         foreach ((array)$needle as $ndl) {
-            $n = mb_strtolower($ndl);
+            $n = mb_strtolower((string) $ndl);
             $length = mb_strlen($ndl);
             if ($length === 0 || (mb_substr($hs, -$length) === $n)) {
                 return true;
diff --git a/helpers/url_helper.php b/helpers/url_helper.php
index a833590..35c9598 100644
--- a/helpers/url_helper.php
+++ b/helpers/url_helper.php
@@ -118,7 +118,7 @@ function encodeId_Url_byHungDEV($id)
      */
     function decodeId_Url_byHungDEV($id)
     {
-        $id = mb_strtoupper($id);
+        $id = mb_strtoupper((string) $id);
         $id = str_replace(
             array('E', 'R', 'M', 'N', 'J', 'I', 'Z', 'K', 'L', 'O'),
             array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9'),
@@ -567,7 +567,7 @@ function convertToLatin($string = '', $alphabetOnly = false, $toLower = true)
                 $output = alphabetOnly($output);
             }
             if ($toLower) {
-                $output = mb_strtolower($output);
+                $output = mb_strtolower((string) $output);
             }
         }
 
diff --git a/src/BaseHelper.php b/src/BaseHelper.php
index 16221ce..4d3b73b 100644
--- a/src/BaseHelper.php
+++ b/src/BaseHelper.php
@@ -19,8 +19,8 @@
  */
 class BaseHelper
 {
-    const VERSION = '1.6.6';
-    const LAST_MODIFIED = '2024-09-15';
+    const VERSION = '1.6.7';
+    const LAST_MODIFIED = '2024-09-22';
     const PROJECT_NAME = 'CodeIgniter - Basic Helper';
     const AUTHOR_NAME = 'Hung Nguyen';
     const AUTHOR_FULL_NAME = 'Hung Nguyen';
diff --git a/src/BasicCurl.php b/src/BasicCurl.php
index fafd59b..7dd00ff 100644
--- a/src/BasicCurl.php
+++ b/src/BasicCurl.php
@@ -199,7 +199,7 @@ private function init()
      */
     public function addResponseHeaderLine($curl, $header_line)
     {
-        $trimmed_header = trim($header_line, "\r\n");
+        $trimmed_header = trim((string) $header_line, "\r\n");
 
         if ($trimmed_header === "") {
             $this->response_header_continue = false;
@@ -802,7 +802,7 @@ public function getResponseHeaders($headerKey = null)
     {
         $headers = array();
         if (!is_null($headerKey)) {
-            $headerKey = strtolower($headerKey);
+            $headerKey = strtolower((string) $headerKey);
         }
 
         foreach ($this->response_headers as $header) {
@@ -811,7 +811,7 @@ public function getResponseHeaders($headerKey = null)
             $key = isset($parts[0]) ? $parts[0] : '';
             $value = isset($parts[1]) ? $parts[1] : '';
 
-            $headers[strtolower(trim($key))] = trim($value);
+            $headers[strtolower(trim((string) $key))] = trim($value);
         }
 
         if ($headerKey) {
diff --git a/src/SimpleRequests.php b/src/SimpleRequests.php
index ddebcd7..8ca2b74 100644
--- a/src/SimpleRequests.php
+++ b/src/SimpleRequests.php
@@ -117,7 +117,7 @@ public function setHeader($header = array())
     public function sendRequest($url = '', $data = array(), $method = 'GET')
     {
         try {
-            $getMethod = mb_strtoupper($method);
+            $getMethod = mb_strtoupper((string) $method);
             if ($this->DEBUG === true) {
                 $this->logger->info('||=========== Logger Send Requests ===========||');
                 $this->logger->info('Send ' . $getMethod . ' Request to URL: ' . $url, $data);
diff --git a/src/Valid.php b/src/Valid.php
index 7179733..60610c5 100644
--- a/src/Valid.php
+++ b/src/Valid.php
@@ -339,7 +339,7 @@ public static function credit_card($number, $type = null)
         );
 
         // Check card type
-        $type = mb_strtolower($type);
+        $type = mb_strtolower((string) $type);
 
         if (!isset($cards[$type])) {
             return false;
diff --git a/src/Validator.php b/src/Validator.php
index 16d87f0..22b9802 100644
--- a/src/Validator.php
+++ b/src/Validator.php
@@ -725,7 +725,7 @@ protected function validateUrlActive($field, $value)
 
         foreach ($this->validUrlPrefixes as $prefix) {
             if (mb_strpos($value, $prefix) !== false) {
-                $host = parse_url(mb_strtolower($value), PHP_URL_HOST);
+                $host = parse_url(mb_strtolower((string) $value), PHP_URL_HOST);
 
                 return checkdnsrr($host, 'A') || checkdnsrr($host, 'AAAA') || checkdnsrr($host, 'CNAME');
             }