Please refer to our support statement here:

In-Place Operating System Upgrades

“The Broadcom engineering team has performed limited testing of in-place upgrades of the operating system on the components of the Symantec Management Platform (i.e., Notification Server, site servers, Internet Gateway and SQL Server) and confirmed no critical issues were found.

 The operating system on a Notification Server running IT Management Suite 8.6 was successfully upgraded in the following scenarios:

• • Windows 2012 R2 Server to Windows 2016 Server
  • Windows 2012 R2 Server OS to Windows 2016 Server and then from Windows 2016 Server to Windows 2022 Server (direct upgrades from Windows 2012 R2 Server to Windows 2022 Server are not supported due to compatibility issues regarding various solutions)
  • Windows 2016 Server to Windows 2022 Server
  • Windows 2019 Server to Windows 2022 Server
    

In cases where the version of Microsoft SQL Server used for the Symantec Configuration Management Database (CMDB) is upgraded, the SQL Server compatibility level for the "Symantec_CMDB" database will need to be adjusted using SQL Management Studio after SQL Server is upgraded.

Broadcom strongly recommends that customers first perform an in-place upgrade in a test environment replicating the production environment as closely as possible to identify potential issues.  In addition, Broadcom strongly recommends backing up the production environment (or creating a snapshot if using a virtualized environment) before performing an in-place upgrade of the operating system, so that you can revert to the prior state if you encounter any issues."

If you need additional information about migrating to a new server instead, we offer the following:

Migration Scenarios and Troubleshooting

Other similar references:

What to Know Before Installing or Upgrading ITMS 8.7

What are the steps for Migrating an 8.x Notification Server to version 8.5?