diff --git a/chart/README.md b/chart/README.md
index 09b8366..012c058 100644
--- a/chart/README.md
+++ b/chart/README.md
@@ -18,7 +18,7 @@ Longhorn is 100% open source software. Project source code is spread across a nu
 ## Prerequisites
 
 1. A container runtime compatible with Kubernetes (Docker v1.13+, containerd v1.3.7+, etc.)
-2. Kubernetes v1.18+
+2. Kubernetes >= v1.21
 3. Make sure `bash`, `curl`, `findmnt`, `grep`, `awk` and `blkid` has been installed in all nodes of the Kubernetes cluster.
 4. Make sure `open-iscsi` has been installed, and the `iscsid` daemon is running on all nodes of the Kubernetes cluster. For GKE, recommended Ubuntu as guest OS image since it contains `open-iscsi` already.