How to fix the Oracle error ORA-15156: cluster in rolling upgrade from version [string] to [string]?

In this post, you’ll learn more about the Oracle ErrorORA-15156: cluster in rolling upgrade from version [string] to [string] with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-15156: cluster in rolling upgrade from version [string] to [string]

Reason for the Error ORA-15156: cluster in rolling upgrade from version [string] to [string]

The current software version of the instance was incompatible with the rolling upgrade operation of the cluster.

How to fix the Error ORA-15156: cluster in rolling upgrade from version [string] to [string] ?

You can fix this error in Oracle by following the below steps

The version number of new member instance must be one of the two versions involved in the rolling upgrade.