diff --git a/docs/tasks/administer-cluster/encrypt-data.md b/docs/tasks/administer-cluster/encrypt-data.md
index 171eae0075..797c2ae957 100644
--- a/docs/tasks/administer-cluster/encrypt-data.md
+++ b/docs/tasks/administer-cluster/encrypt-data.md
@@ -14,6 +14,8 @@ This page shows how to enable and configure encryption of secret data at rest.
 
 * Kubernetes version 1.7.0 or later is required
 
+* etcd v3 or later is required
+
 * Encryption at rest is alpha in 1.7.0 which means it may change without notice. Users may be required to decrypt their data prior to upgrading to 1.8.0.
 
 {% endcapture %}