Hi strictly speaking we should not have the 2nd server taking calls while the primary is being upgraded but we are adding an additional language - could the 2nd server be left as active while the upgrade is being done on Primary?..cheers, Jag
After some more digging, adding a language actually constitutes a software upgrade, which is categorized differently than simply applying an ES to the primary, while failing over to the secondary and have it take calls. Upgrades require both servers be out of service:
Sorry for the confusion. So, you'll want to ultimately do this off hours.