Symptom:
If you deploy a HA system with 2.0 OVA ( 2.0 MR1), then configure it, and reach the congratulation page, then Run the Update to 2.5. The Update in the backedn works , but the web page reports an error "Please try again as the server encountered an unexpected error..."

Conditions:
This issue impacts to system which has been Updated from current existing any 2.0 version to 2.5, and need to add HA after Update.  Before add HA, the HA alone system will be installed with 2.0 MR1 OVA in this case, and Update it to 2.5 directly  runs into the issue.

Standalone HA (built with 2.0 FCS or 2.0 MR1 OVA), then update to 2.0 MR3 or MR4,  then update to 2.5 also experiences this failure.