increase required PHP version

Author: JBlond

README.md

@@ -30,7 +30,8 @@ example.php.
 
 Requirements
 -----------
-PHP Multibyte String 
+- PHP 7.1 or greater
+- PHP Multibyte String 
 
 Merge files using jQuery
 ------------------------
@@ -50,6 +51,7 @@ Contributors since I forked the repo.
 
 - maxxer
 - Creris
+- jfcherng
 
 License (BSD License)
 ---------------------

composer.json

@@ -18,7 +18,7 @@
         }
     ],
     "require": {
-        "php" : ">= 5.4",
+        "php" : ">= 7.1",
         "ext-mbstring": "*"
     },
     "require-dev": {