The current node {0} is at patch level {1}], which is lower than that of active node {2}: patch level {3}]. After completing ...

The current node {0} is at patch level [{1}], which is lower than that of active node {2}: patch level [{3}]. After completing setup, you must download and apply the latest SQL Server 2008 R2 service pack and/or patch and bring all nodes to the same version and patch level.