diff --git a/composer.json b/composer.json
index 09325c9..884d2c8 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
     ],
     "require": {
         "php": "^5.6",
-        "ext-json": "^1.2"
+        "ext-json": "*"
     },
     "require-dev": {
         "phpunit/phpunit": "^5.7",