With the first anniversary of OnePlus One on 23 April, the manufacturer has announced its 2014 flagship smartphone will be available for purchase directly, without an invite, starting on 20 April.

"That's right. In our first big celebration of the One's successful year, we are opening up sales globally for everyone, every day of the week. We have always wanted to put great products into the hands of more people. And, we now feel confident that we have matured enough to handle the increased complexity that comes along with opening up sales completely," said the company.

Chinese startup OnePlus confirmed to follow a similar transition with its next flagship handset, OnePlus 2, which will be initially launched with invites.

The company said: "The OnePlus 2 will bring the challenges that come along with a brand new product, and initially, our invite system will help us to manage that risk. It also helps us to be sure that every OnePlus 2 user gets the amazing experience that they deserve."

Besides, the company is offering a 75% discount on OnePlus Flip Covers and its premium screen protectors. The offer is valid for just 24 hours. The Bamboo StyleSwap covers will be available without any invitation. Theses promotion offers are valid for regions such as USA, Canada, the European Union, Hong Kong and Taiwan.

"Our invite system has been a fascinating, evolving experiment. Within the community, feelings towards our invite system vary, and we understand that. The reality is that we wouldn't be where we are today without it. But, as always, we are listening. Your feedback significantly alters our trajectory, and we wouldn't have it any other way. Keep being loud, bold and honest; we'll promise to do the same," added the company.

The OnePlus One has been sold more than one million units worldwide since its launch.