The latest major release of Xiaomi's popular mobile OS has been in the works for some time now. As originally promised, after two weeks or so of closed beta testing, the ROM is now available for download, so you can get it and test it on your Xiaomi device for yourself. Currently, there are builds for the Mi 2, Mi 2S, Mi 3, Mi 4, Mi 5, Mi Note and Mi Max. For any of these, you can hit the source link and download a copy right now. According to the original release schedule, a Developer ROM should be made available on June 17, which will also add support for the Mi 4C, Mi 4S, as...
Source: http://www.gsmarena.com/miui_8_open_beta_is_now_available_for_download-news-18557.php