Hi Bye,
There are total thee ways to downgrade vSZ.
1st: If a cluster backup was created during lastupgrade or before, then you can easily restore it and system will downgrade to previousversion with all the settings.
3rd: If no cluster or configuration backup availablethen downgrading vSZ will factory reset its configuration and you have to reconfigureit from the scratch.
IMPORTANT NOTE: All 3 ways required downtime as system will restart or reconfiguration will be required.
Regards,
Syamanak Omer