Maintenance update: Increased minimum PHP version to 7.4, added params and return types, added DocBlocks

Author: Geolim4

composer.json

@@ -20,7 +20,8 @@
             }
         ],
     "require": {
-        "php": ">=5.4.0"
+        "php": ">=7.4.0",
+        "ext-json": "*"
     },
     "autoload": {
         "psr-4": {