Upgrading or downgrading the Citrix ADC cluster

All the nodes of a Citrix ADC cluster must be running the same software version. Therefore, to upgrade or downgrade the cluster, you must upgrade or downgrade each Citrix ADC appliance of the cluster, one node at a time.

A node that is being upgraded or downgraded is not removed from the cluster. The node continues to be a part of the cluster and serves traffic uninterrupted, except for the down-time when the node reboots after it is upgraded or downgraded.

When you upgrade or downgrade the first cluster node, you must not perform any configurations through the cluster IP while the node reboots.

After the first cluster node reboots, configuration propagation is disabled on the cluster due to a software version mismatch among the cluster nodes. Configuration propagation is enabled only after you upgrade or downgrade all the cluster nodes. Since configuration propagation is disabled during the upgrade or downgrade of a cluster, you cannot perform any configurations through the cluster IP address during this time.


  • Configurations can be lost on downgrading the cluster.

Points to note before upgrading or downgrading the cluster

  • You cannot add cluster nodes while upgrading or downgrading the cluster software version.

  • You can perform node-level configurations through the NSIP address of individual nodes, but make sure to perform the same configurations on all the nodes to maintain them in synch.

  • You cannot execute the “start nstrace” command from the cluster IP address when the cluster is being upgraded. However, you can get the trace of individual nodes by performing this operation on individual cluster nodes through their NSIP address.

  • When a cluster is being upgraded, it is possible that the upgraded nodes have some additional features activated that are not available on the nodes that are not upgraded. This results in a license mismatch warning while the cluster is being upgraded. This warning will be automatically resolved when all the cluster nodes are upgraded.


  • Citrix recommends that you wait for the previous node to become active before upgrading or downgrading the next node.

  • Citrix recommends that the cluster configuration node must be upgraded/downgraded last to avoid multiple disconnect of cluster IP sessions.

To upgrade or downgrade the software of the cluster nodes

  1. Make sure the cluster is stable and the configurations are synchronized on all the nodes.

  2. Access each node through its NSIP address and perform the following:

    • Upgrade or downgrade the cluster node. For detailed information about upgrading and downgrading the software of an appliance, see Upgrade and downgrade a NetScaler appliance.

    • Save the configurations.

    • Reboot the appliance.

  3. Repeat step 2 for each of the other cluster nodes.

Upgrading or downgrading the Citrix ADC cluster