add php min, require php >= 8.1

src/Backend.php

@@ -24,7 +24,9 @@ class Backend extends dcNsProcess
 {
     public static function init(): bool
     {
-        self::$init = defined('DC_CONTEXT_ADMIN');
+        if (defined('DC_CONTEXT_ADMIN')) {
+            self::$init = dcCore::app()->auth->isSuperAdmin() && version_compare(phpversion(), My::PHP_MIN, '>=');
+        }
 
         return self::$init;
     }

src/Config.php

@@ -33,7 +33,13 @@ class Config extends dcNsProcess
 {
     public static function init(): bool
     {
-        self::$init = defined('DC_CONTEXT_ADMIN');
+        if (defined('DC_CONTEXT_ADMIN')) {
+            if (version_compare(phpversion(), My::PHP_MIN, '>=')) {
+                self::$init = true;
+            } else {
+                dcCore::app()->error->add(sprintf(__('%s required php >= %s'), My::id(), My::PHP_MIN));
+            }
+        }
 
         return self::$init;
     }

src/My.php

@@ -18,6 +18,9 @@ use dcCore;
 
 class My
 {
+    /** @var string Required php version */
+    public const PHP_MIN = '8.1';
+
     /** @var array Excluded files */
     public const EXCLUDED_FILES = [
         '.',