Version 2.0: PHP 8.1

composer.json

@@ -9,13 +9,13 @@
     },
     "extra":             {
         "branch-alias": {
-            "dev-master": "1.x-dev"
+            "dev-master": "2.x-dev"
         }
     },
 
     "minimum-stability": "stable",
     "require":           {
-        "php": "^7.4 || ^8.0"
+        "php": "^8.1"
     },
     "autoload":          {
         "psr-4":                 {

src/Singleton/ISingleton.php

@@ -15,5 +15,5 @@ interface ISingleton {
      *
      * @return static The instance
      */
-    public static function getInstance (): self;
+    public static function getInstance (): static;
 }

src/Singleton/TSingleton.php

@@ -25,7 +25,7 @@ trait TSingleton {
     /**
      * @inheritDoc
      */
-    public static final function getInstance (): self {
+    public static final function getInstance (): static {
         if (!isset(self::$singletonInstance)) {
             self::$singletonInstance = new static();
         }