Greetings, Nomads! The test will take place on official servers just as the last test did. No launch parameters are required and ensure that you have selected the default branch "None" in beta options, as shown below.
All servers will go down shortly for approximately two hours, after which the test will begin! Also, as a bit of a house-keeping announcement, upon the launch of Season 6, we will be shutting down the S4 backend, so you will no longer be able to host servers based on the S4 version of the game. Plan accordingly.