diff --git a/docs/releases/1.20-NOTES.md b/docs/releases/1.20-NOTES.md
index 17d5d776f0..83a15c3b4b 100644
--- a/docs/releases/1.20-NOTES.md
+++ b/docs/releases/1.20-NOTES.md
@@ -10,6 +10,8 @@
 
 * Following kubeadm, control plane nodes are now labelled with `node-role.kubernetes.io/control-plane=""`
 
+* Default node image for GCE changed from COS to Ubuntu for K8s versions >= 1.17.0. This is to more closely align with the AWS implementation (the most mature support) and because COS limits the ability to modify files on its disk.
+
 # Breaking changes
 
 * Support for Kubernetes 1.11 and 1.12 has been removed.