According to users over on the Xiaomi forums, the update, marked a "stable beta" is now rolling out to users in China. The device, released in February, is still running Android 7.1 Nougat; however this update should bring all the latest features and functionality that Xiaomi tend to pack into their MIUI skin.
While stable beta may be a bit of an oxymoron, we'll assume that the latest build is at a suitable and safe threshold for your daily driver. As we haven't gotten our hands on an official changelog yet, it's difficult to say with any degree of certainty which features have been ported over to the Redmi Note 4X on MIUI 9, and what bugs and issues remain present in this early build. Obviously it is important that whenever installing beta builds that you backup first and proceed with caution; unlicensed or prerelease software always has the potential to brick your device.
A notable practice of Xiaomi's is how they largely ignore Google's year-by-year iterative Android update cycle on their devices. Instead, they update MIUI for all devices which they wish to roll out the update to and implement the necessary new features or additional functionality, regardless of what version of Android you're on. An example of this is the 5-year-old Xiaomi Mi 2, which is amazingly going yo be updated to MIUI 9! Xiaomi is sending strong signals to Google to up their game, and increasing their chances of dominance over the smartphone market over the next few years. All in all, we're excited to see what Xiaomi does next.
What do you guys think? Will you download this build? Is MIUI your thing? Let us know in the comments, or post over in the forums with your thoughts.