diff --git a/clusterSystemUpgrade.yml b/clusterOSUpgrade.yml
similarity index 100%
rename from clusterSystemUpgrade.yml
rename to clusterOSUpgrade.yml
diff --git a/clusterUpgrade.yml b/clusterUpgrade.yml
index 7074fda..0cd48ac 100644
--- a/clusterUpgrade.yml
+++ b/clusterUpgrade.yml
@@ -16,6 +16,10 @@
         name: install
         tasks_from: download
 
+    - name: copy mtls/sasl files
+      ansible.builtin.import_role:
+        name: copyFiles
+
     - name: configuring latest Zookeeper version
       ansible.builtin.import_role:
         name: configure
diff --git a/inventory/development/group_vars/all.yml b/inventory/development/group_vars/all.yml
index a919b71..4f9a395 100755
--- a/inventory/development/group_vars/all.yml
+++ b/inventory/development/group_vars/all.yml
@@ -68,8 +68,8 @@ zookeeperPrometheusExporterEnabled: true
 zookeeperPrometheusExporterHttpPort: 7000
 
 # zookeeper versions
-zookeeperVersion: 3.8.0
-zookeeperOldVersion: 3.7.1 # only used in removing old versions
+zookeeperVersion: 3.9.1
+zookeeperOldVersion: 3.8.0 # only used in removing old versions
 
 # use local tar only
 zookeeperTarLocation: "/home/pox/zookeeper-cluster-ansible/apache-zookeeper-{{ zookeeperVersion }}-bin.tar.gz"
diff --git a/readme.md b/readme.md
index bbaec06..dfffc5c 100644
--- a/readme.md
+++ b/readme.md
@@ -84,6 +84,10 @@ ansible-playbook -i inventory/<environment>/cluster.ini clusterConfigsUpdate.yml
 ansible-playbook -i inventory/<environment>/cluster.ini clusterConfigsUpdate.yml -e zookeeperConfigFile=jaas.conf
 ansible-playbook -i inventory/<environment>/cluster.ini clusterConfigsUpdate.yml -e zookeeperConfigFile=logback.xml
 ```
+### **To upgrade zookeeper version of cluster**
+* Update Required vars in ```inventory/<environment>/group_vars/all.yml``` .
+
+```ansible-playbook -i inventory/<environment>/cluster.ini clusterUpgrade.yml```
 
 ### **To upgrade java version of cluster**
 * Update Required vars in ```inventory/<environment>/group_vars/all.yml``` .
@@ -93,7 +97,7 @@ ansible-playbook -i inventory/<environment>/cluster.ini clusterConfigsUpdate.yml
 ### **To upgrade OS version of cluster**
 * Update Required vars in ```inventory/<environment>/group_vars/all.yml``` .
 
-```ansible-playbook -i inventory/<environment>/cluster.ini clusterSystemUpgrade.yml```
+```ansible-playbook -i inventory/<environment>/cluster.ini clusterOSUpgrade.yml```
 
 ### **To remove old version files of zookeeper from cluster**
 * Update Required vars in ```inventory/<environment>/group_vars/all.yml``` .
diff --git a/roles/configure/templates/logback.xml b/roles/configure/templates/logback.xml
index b29133a..bd7c507 100644
--- a/roles/configure/templates/logback.xml
+++ b/roles/configure/templates/logback.xml
@@ -23,7 +23,7 @@
   <!-- Uncomment this if you would like to expose Logback JMX beans -->
   <!--jmxConfigurator /-->
 
-  <property name="zookeeper.console.threshold" value="WARN" />
+  <property name="zookeeper.console.threshold" value="ERROR" />
 
   <property name="zookeeper.log.dir" value="{{ zookeeperLogDir }}" />
   <property name="zookeeper.log.file" value="zookeeper.log" />