Hello @Handian Sudianto ,
You are right, you can follow this update path:
->Proceed with the upgrades in order: 10.2411.3.2 -> 2503 -> 2504 -> 2509.
->Check for "Opt-in" or "Train Update" at 2509: Once you are on version 2509 (OS Build 25398.xxx), do not simply apply the default 2510 update.
You must look for a specific update, patch, or "opt-in" option that is explicitly described as moving you to the OS 26100 train. This might be listed in your Azure update portal as a separate offering or require a specific configuration.