Bhupesh,
1. For upgrading acs to 4.x code you need have software upgrade contract i.e you need to purchase it.
Did you try the workaround , that should fix it ?
2. You can upgrade acs one by one. Upgrade secondary first, and see if uses can authenticate with that. If all is well upgrade primary acs.
Till that time replication will not work as both acs would have different software ver.
If you plan to upgrade , then upgrade acs to 4.1.1 patch 5 instead of 4.0
Upgrade path
3.3.3---->4.1.1---->4.1.1 patch 5
Find attached the upgrade steps on acs appliance.
Regards,
~JG
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