There is no enablement package available for upgrade to Windows 11 24H2, so an ISO based upgrade is required. Starting from PMImport 7.4.1622 there is the SBSP-Windows11_24H2 bulletin to facilitate this upgrade scenario.
Please note that it is applicable to Windows 11 to Windows 11 upgrade, corresponding bulletin is not applicable for Windows 10 installations.
ITMS 8.7.x
Use the usual process to upload manually downloaded updates to the policy to provide the required ISO files and then enable the advertisements and policy after this.
The update installation starts the Windows 11 upgrade process and this will require several computer restarts to complete.
Troubleshooting:
"Upgrading to Windows 11 using Software Management Solution" (KB 249016)