diff --git a/composer.json b/composer.json
index b0d5836..02a4572 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,8 @@
         "silverstripe/reports": "4.x-dev",
         "silverstripe/siteconfig": "4.x-dev",
         "silverstripe/versioned": "1.x-dev",
-        "silverstripe/graphql": "3.x-dev || 4.x-dev"
+        "silverstripe/graphql": "3.x-dev || 4.x-dev",
+        "silverstripe/session-manager": "1.x-dev"
     },
     "require-dev": {
         "sminnee/phpunit": "^5.7",