diff --git a/defaults/main.yml b/defaults/main.yml
index 1ed1d14..ca3db9d 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -1,5 +1,6 @@
 ---
-mongodb_version: 3.6
+# currently only 3.4 is supported by ubiquiti
+mongodb_version: 3.4
 mongodb_system_user: mongod
 mongodb_system_group: mongod
 # mongodb_system_gid: omit