diff --git a/composer.json b/composer.json
index 59a8daeb90deccb21961111569eced732c3c3602..29aa586ed1af5f5b708691050fb3c9ba7e1de19c 100644
--- a/composer.json
+++ b/composer.json
@@ -86,6 +86,7 @@
     },
     "require-dev": {
         "ext-curl": "*",
+        "ext-krb5": "*",
         "mikey179/vfsstream": "~1.6",
         "phpunit/phpunit": "~5.7"
     },