diff --git a/composer.json b/composer.json
index 4ae78d48ea..716df6cb09 100644
--- a/composer.json
+++ b/composer.json
@@ -35,7 +35,7 @@
         "php": "^5.4 || ^7.0 || ^8.0",
         "ext-gd": "*",
         "ext-mbstring": "*",
-        "mobiledetect/mobiledetectlib": "^2.8",
+        "mobiledetect/mobiledetectlib": "^3.74",
         "nanasess/mdb2": "^2.5",
         "nanasess/php8-compat": "^1.0",
         "pear/archive_tar": "^1.4.3",
diff --git a/composer.lock b/composer.lock
index f36f0c768d..a1c6b82a93 100644
--- a/composer.lock
+++ b/composer.lock
@@ -8,31 +8,33 @@
     "packages": [
         {
             "name": "mobiledetect/mobiledetectlib",
-            "version": "2.8.45",
+            "version": "3.74.3",
             "source": {
                 "type": "git",
                 "url": "https://github.com/serbanghita/Mobile-Detect.git",
-                "reference": "96aaebcf4f50d3d2692ab81d2c5132e425bca266"
+                "reference": "39582ab62f86b40e4edb698159f895929a29c346"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/serbanghita/Mobile-Detect/zipball/96aaebcf4f50d3d2692ab81d2c5132e425bca266",
-                "reference": "96aaebcf4f50d3d2692ab81d2c5132e425bca266",
+                "url": "https://api.github.com/repos/serbanghita/Mobile-Detect/zipball/39582ab62f86b40e4edb698159f895929a29c346",
+                "reference": "39582ab62f86b40e4edb698159f895929a29c346",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.0.0"
+                "php": ">=7.4"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.8.36"
+                "friendsofphp/php-cs-fixer": "^3.14",
+                "phpunit/phpunit": "^9.6",
+                "squizlabs/php_codesniffer": "^3.7"
             },
             "type": "library",
             "autoload": {
-                "psr-0": {
-                    "Detection": "namespaced/"
+                "psr-4": {
+                    "Detection\\": "src/"
                 },
                 "classmap": [
-                    "Mobile_Detect.php"
+                    "src/MobileDetect.php"
                 ]
             },
             "notification-url": "https://packagist.org/downloads/",
@@ -43,7 +45,7 @@
                 {
                     "name": "Serban Ghita",
                     "email": "serbanghita@gmail.com",
-                    "homepage": "http://mobiledetect.net",
+                    "homepage": "https://mobiledetect.net",
                     "role": "Developer"
                 }
             ],
@@ -58,7 +60,7 @@
             ],
             "support": {
                 "issues": "https://github.com/serbanghita/Mobile-Detect/issues",
-                "source": "https://github.com/serbanghita/Mobile-Detect/tree/2.8.45"
+                "source": "https://github.com/serbanghita/Mobile-Detect/tree/3.74.3"
             },
             "funding": [
                 {
@@ -66,7 +68,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2023-11-07T21:57:25+00:00"
+            "time": "2023-10-27T16:28:04+00:00"
         },
         {
             "name": "nanasess/mdb2",
diff --git a/data/class/SC_SmartphoneUserAgent.php b/data/class/SC_SmartphoneUserAgent.php
index 0e4d5a66a3..22b8ea1f65 100644
--- a/data/class/SC_SmartphoneUserAgent.php
+++ b/data/class/SC_SmartphoneUserAgent.php
@@ -21,6 +21,8 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
+use Detection\MobileDetect;
+
 /**
  * スマートフォンの情報を扱うクラス.
  *
@@ -36,7 +38,7 @@ class SC_SmartphoneUserAgent
      */
     public static function isSmartphone()
     {
-        $detect = new Mobile_Detect;
+        $detect = new MobileDetect();
         // SPでかつPC表示OFFの場合
         // TabletはPC扱い
         return ($detect->isMobile() && !$detect->isTablet()) && !SC_SmartphoneUserAgent_Ex::getSmartphonePcFlag();