diff --git a/composer.json b/composer.json
index 25d18e0..478052f 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,8 @@
     },
     "require": {
         "php": ">=5.0.0",
-        "ext-curl": "*"
+        "ext-curl": "*",
+        "ext-simplexml": "*"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.1",