Symantec DCS is integrated with vCenter/NSX and either the NSX Manager, vCenter, Symantec DCS or all of them need to be upgraded or reinstalled.
VMWare NSX Manager
When upgrading or reinstalling multiple changes are made and integration may cause problems.
Also, when upgrading or reinstalling some of these changes will impact the functionality of the integration.
It is required to Unregister the vCenter/NSX connection in UMC's Integration page before upgrading/changing Symantec DCS, vCenter or NSX.
To unregister there are a couple things that must be done first.
Remove Symantec Threat Protection Service from Security Policies
Undeploy the Symantec Threat Protection Service
Unregister vCenter/NSX from Symantec DCS
When these steps are all finished you can make the needed changes.