Yes you can, If you are upgrading from Spotlight on Messaging to UCCS Diagnostics there are a few things to consider.
If you are upgrading from a previous version of Spotlight on Messaging, you must first export your topology layouts from Spotlight on Messaging before you install UCCS - Diagnostics. For more information have a look at the UCCS Diagnostics Release notes included with your UCCS Download.
If you are using Web Reports subscriptions, you must export your subscriptions from Spotlight on Messaging and
import them to UCCS - Diagnostics. For more information have a look at the UCCS Diagnostics Release notes included with your UCCS Download.
Important Note: This new release of Unified Communications Command Suite - Diagnostics 8.0 requires a new license key. Please obtain the new key before you install the new release. To obtain a new key, refer to the License Key Upgrade page: https://support.quest.com/contact-us/licensing
For more detailed information on your Upgrade/Install consult the the UCCS_Diagnostics_Deployment_Guide.pdf included with your UCCS download.