diff --git a/15_etcd/15.3_cluster.md b/15_etcd/15.3_cluster.md
index 151d64b..44a2fb4 100644
--- a/15_etcd/15.3_cluster.md
+++ b/15_etcd/15.3_cluster.md
@@ -8,7 +8,7 @@
 services:
 
   node1:
-    image: quay.io/coreos/etcd:v3.4.0
+    image: quay.io/coreos/etcd:v3.5.17
     volumes:
       - node1-data:/etcd-data
     expose:
@@ -40,7 +40,7 @@ services:
       - docker-etcd
 
   node2:
-    image: quay.io/coreos/etcd:v3.4.0
+    image: quay.io/coreos/etcd:v3.5.17
     volumes:
       - node2-data:/etcd-data
     networks:
@@ -72,7 +72,7 @@ services:
       - docker-etcd
 
   node3:
-    image: quay.io/coreos/etcd:v3.4.0
+    image: quay.io/coreos/etcd:v3.5.17
     volumes:
       - node3-data:/etcd-data
     networks:
diff --git a/15_etcd/demo/cluster/docker-compose.yml b/15_etcd/demo/cluster/docker-compose.yml
index 43d7a06..0069343 100644
--- a/15_etcd/demo/cluster/docker-compose.yml
+++ b/15_etcd/demo/cluster/docker-compose.yml
@@ -2,7 +2,7 @@ version: "3.6"
 services:
 
   node1:
-    image: quay.io/coreos/etcd:v3.4.0
+    image: quay.io/coreos/etcd:v3.5.17
     volumes:
       - node1-data:/etcd-data
     expose:
@@ -34,7 +34,7 @@ services:
       - docker-etcd
 
   node2:
-    image: quay.io/coreos/etcd:v3.4.0
+    image: quay.io/coreos/etcd:v3.5.17
     volumes:
       - node2-data:/etcd-data
     networks:
@@ -66,7 +66,7 @@ services:
       - docker-etcd
 
   node3:
-    image: quay.io/coreos/etcd:v3.4.0
+    image: quay.io/coreos/etcd:v3.5.17
     volumes:
       - node3-data:/etcd-data
     networks: