diff --git a/composer.json b/composer.json
index a5170aa..d23e508 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
     "require": {
         "php": ">=5.6",
         "guzzlehttp/guzzle": "^6.0",
-        "jms/serializer": "^1.2",
+        "jms/serializer": "1.2.0",
         "psr/log": "^1.0",
         "nesbot/carbon": "^2.0.0",
         "symfony/yaml": "^3.1"