diff --git a/composer.json b/composer.json
index c4f416a..2877a43 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,8 @@
     ],
     "require": {
         "php": "^7.1",
-        "myclabs/php-enum": "^1.6"
+        "myclabs/php-enum": "^1.6",
+        "ext-iconv": "*"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.0",