During installation, the installer surveys the software that is already installed on the host where you are installing and identifies the following:
Compatible product components are installed.
Compatible product components do not need to be reinstalled and will not be available for selection in the installer.
Incompatible product components are installed.
If the installer identifies incompatibilities between product components you have selected and product components that are already installed locally, you might be prompted to remove or upgrade the incompatible installed product component. The installer cannot continue until these incompatibilities are resolved. If a component shows as upgradable at component selection, you can go back to the first page of the installer and choose to Upgrade instead of Install. For additional information on upgrading incompatible product components, refer to How Upgrading Works.
Incompatible shared components are installed.
It is not uncommon for existing hosts to already contain versions of shared components, such as J2SE or NSS. If the installer finds shared components whose version is incompatible with the version of Communications Suite you are installing, those shared components are listed. If you proceed with installation, the installer automatically upgrades the shared components to compatible versions.