You do not need to place the cluster in non-cluster mode before performing this upgrade because the upgrade always occurs in the new boot environment and the existing boot environment remains unchanged. You can specify a name for the new boot environment or you can use the auto-generated name. For instructions, see How to Upgrade the Software (Standard Upgrade) in Oracle Solaris Cluster Upgrade Guide .
Anytime you upgrade the Oracle Solaris Cluster software, you should also upgrade the data services and Geographic Edition software. However, if you want to upgrade the data services separately, see Overview of the Installation and Configuration Process in Oracle Solaris Cluster Data Services Planning and Administration Guide . If you want to upgrade Oracle Solaris Cluster Geographic Edition separately, see the Oracle Solaris Cluster Geographic Edition Installation Guide .
The Oracle Solaris OS is also updated to the latest release when you upgrade the Oracle Solaris Cluster software.