OnePlus has just announced that they will be introducing a new invite system for the successor of the OnePlus One. They are also introducing physical cards that can be used as invites to purchase the OnePlus 2.
The OnePlus 2 will also have an invite system but since they are confident about the demand and the way they can supply, they are planning to have about 30-50 times the number of invites they had last year for the OnePlus One. This will make it easier to get an invite even during the initial sales period too.
These invites will start rolling out first to members who are active on the OnePlus forums. However, they will also have a reservation system that will allow people to receive an invite as and when available without having to participate in the forum.
Lastly, you will also be able to receive shareable invites after you make a purchase but this time around, those shareable invites will arrive in your account much faster than last time.