A DDC 2402 LTSR CU is successfully installed in a server. When creating a new site through Citrix Site Manager wizard, another server address which hosts SQL Server 2016 SP2 is specified.
After the wizard finishes, a site database creation error is prompted with Error Id: XDSM:2D93F726, indicating "Failed to update database <SiteDB_Name> on server <SQLServer_Address>".
Expanding the error details will show exception message Microsoft.Data.SqlClient.SqlException **** ERROR **** : Citrix Monitor Service: Schema creation requires SQL Server 2019 or later.

SQL Server 2016 SP2 indeed meets the system requirement of CVAD 2402 LTSR. However, upon the DDC 2402 LTSR CU installation, "Install Director Current Release" option was ticked in the installation wizard. As a result, a CR version Citrix Monitor Service was installed, whose DB schema creation requires SQL Server 2019 or later. The SQL Server version discrepancy caused the site DB creation failure.

To address the issue, please upgrade the SQL Server 2016 SP2 to 2019 or later, or keep the SQL Server version unchanged and take the following steps,

1. In Windows Control Panel, uninstall the following Citrix components.

• Citrix Director
• Citrix Monitor Service - x64
• Citrix Monitor Service PowerShell snap-in - x64
• Citrix Virtual Apps and Desktops 7 2402 LTSR CU

2. Reinstall DDC 2402 LTSR CU. and untick "Install Director Current Release" option in "Features" tab of the installation wizard

The article describes a CVAD 2402 LTSR CU site database creation error due to the discrepancy between the installed Monitor Service version and SQL Server version.