...
The Standard upgrade procedure should be used when it is required to minimize downtime during upgrade and to ensure that configurations, persisted data (in the file system or database), and system properties are properly migrated. The Standard upgrade procedure needs to be done step-wise via every minor and majorMediationZone 9.1 can be done by upgrading from MediationZone 8.3.x or MediationZone 9.0.x.
The Simplified Upgrade procedure should be used when this is not required, and you only wish to migrate configuration data. The Simplified upgrade procedure can be done over multiple majors and minors in one upgrade.
...