Patent attributes
An application includes main program code, but also a call handler and an update module. When a specific method or function in the operating system is called, the call is redirected to the call handler in the application. The call handler then calls the function in the operating system. The function retrieves an object to present in a user interface to the application. But before the object is rendered, program control is returned to the call handler, which calls into the update module. The update module determines whether or not the appearance of the object should be changed, for example, in accordance with an A/B test or any other type of update. If so, visual characteristics of the object are changed. Control reverts back to the operating system from the call handler and the object, in its changed form, is presented in the user interface.

