Either their manufacturing process has improved, or the folks at OnePlus aren't selling too many of their OnePlus X. The device just came out at the end of last year, and already the company is ditching their controversial invite system... the OnePlus X invite went free forever now.
Sadly, this does not mean that their much hated "invite system" will be going away for future models. In fact, Carl Pei of OnePlus recently shared that he doesn't see the system going away completely for years to come. It looks like that is simply the price the company must pay to be able to find success as a lone startup smartphone OEM.
Here's our dedicated OnePlus X section for further discussion: OnePlus X