You have been assigned one or more 31-character keys that identify your test sessions for US Core v4.0.0 and v6.1.0. This key is used to direct your web browser to the appropriate page for testing either version. Enter your key in the input control above and then activate the button for testing US Core v4.0.0 or US Core v6.1.0. Your web browser will be directed to the correct page.
If you enter an incorrect key value, the system with give you a "Not Found" error.