Effective in version 10.3 HotFix 3, Zero Downtime (ZDT) upgrade is deferred and is unavailable because of the changes to the mode of authentication for Multidomain MDM.
Informatica intends to reinstate upgrade with ZDT in an upcoming release. If you purchased the ZDT module, we recommend that you wait for ZDT to become available before you upgrade. For more information, contact Informatica Global Customer Support.