Highlighted features of MIUI 8 Global Beta version 6.7.21 includes fingerprint support for second space, auto adjustment when photo sharing, delete button on screenshot preview page as well as optimization for time, date, and weather adjustments in the status bar. However, the ROM still skips Xiaomi Mi 5 and Redmi 3.
Below are the new features of MIUI 8 Global Beta ROM v6.7.21. You can read full changelog of this update from the source link (given at the end of this post) MIUI 8 Global Public Beta supported devices: Redmi 1S, Redmi 2, Redmi 2 Prime, Mi 3, Mi 4, Redmi Note 3 Qualcomm, Mi 4i, Redmi Note 2, Redmi Note 4G, Redmi Note Prime, Mi Max 32GB, Mi 2/2S, Mi 5, Mi Note, Redmi 3 MIUI 8 Global beta ROM (Fastboot/Recovery image) can be downloaded for supported devices from here [HERE]. This step-by-step guide let you know how to flash MIUI 8 ROM on your device. The fastboot method requires ADB and fastboot drivers installed on your computer. Note: The status of MIUI 8 Global ROM is Beta, which means it is unstable and may include bugs that are not yet identified. Normal users are advised to wait for the stable build of MIUI 8, which is scheduled to release in next month (August 23). (Source)