You can downgrade to any release on a high availability pair by using the command line interface. The NetScaler GUI does not support the downgrade process.
To downgrade the system software on NetScaler units in a high availability pair, you need to downgrade the software first on the secondary node and then on the primary node. For instructions on downgrading each node separately, see "Downgrading a NetScaler Standalone Appliance".
Loss in configuration might occur when downgrading. You should compare the configurations before and after the downgrade, and then manually re-enter any missing entries.