As previously announced, we are conducting a mass test on the Singularity test server this Thursday 12 August at 17:00 UTC. Information on what exactly will be tested can be found in the dedicated thread on EVE Online forums.
To join the masstest, you must be running the latest version of the EVE Online launcher. Both macOS and Windows users will be able to join. The more players that join in, the better the data gathered which will inform the future of EVE. Please read the rules for Singularity before you join, as these are different from those that guide users on the main server, Tranquility.
There is also an FAQ on Singularity that is recommend reading for playtesters, especially if you experience login problems.