OnePlus will be starting a new Closed Beta program that will consist of a special group of testers who will be directly interfacing with OnePlus's staff to test out very early software releases before they are seeded to Open Beta testers and consequently to the public. There are certain requirements to qualify for the Closed Beta and OnePlus will be recruiting only 100 people for this program.
https://www.notebookcheck.net/OnePlus-to-start-an-elite-beta-testing-group.324080.0.html