You can choose to perform an initial installation or, if your system is already running the Solaris OS, you can upgrade your system.
An initial installation overwrites the system's disk with the new version of the Solaris OS. If your system is not running the Solaris OS, you must perform an initial installation.
If the system is already running the Solaris OS, you can choose to perform an initial installation. If you want to preserve any local modifications, before you install, you must back up the local modifications. After you complete the installation, you can restore the local modifications.
You can use any of the Solaris installation methods to perform an initial installation. For detailed information about the different Solaris installation methods, refer to Choosing a Solaris Installation Method.
You can upgrade the Solaris OS by using two upgrade methods: standard and Solaris Live Upgrade. A standard upgrade maintains as many existing configuration parameters as possible of the current Solaris OS. Solaris Live Upgrade creates a copy of the current system. This copy can be upgraded with a standard upgrade. The upgraded Solaris OS can then be switched to become the current system by a simple reboot. If a failure occurs, you can switch back to the original Solaris OS with a reboot. Solaris Live Upgrade enables you to keep your system running while you upgrade and enables you to switch back and forth between Solaris OS releases.
For more information about upgrading and the list of upgrade methods, see Upgrade Planning.