If you deliver an update of your application, the license file on the customer system includes all license information and there is no need to send out a new Serial Number.
In case your update includes new modules / features, you can change the license file structure using the following API commands
•getModuleList - Retrieves a list of all modules
•addModule - Add a new module to the existing license file
•deleteModule - Deletes an existing module in the license file
•existsModule - Checks if a module is available in the license file