Yesterday Xiaomi and Microsoft released Windows 10 for MI 4 LTE, and now Xiaomi announced that MIUI7 will be updated with Marshmallow in next week but Starting from china Rom, then after that Global beta and then Stable Rom. Overall according to Approximation, you have to wait till February. in Feb 2016 They Might Release a Global Marshmallow Update. Let’s see After Next Week for China Beta ROM for Testings! It is Officially Announced for China ROM So, No worries MIUI7 will be Updated in Upcoming month.
It’s been almost four months since the launching of MIUI 7. During this time, MIUI devs have been working to bring the new Android versions to our devices.
Here’re some good news: Mi 3 W/C, Mi 4 and Mi Note will be the first ones to get Android M (6.0)! The beta updates will roll out for them soon. From next week, these three devices will no longer get updates based on Android Kitkat (4.4). -Official Statement
Mi 4 TD/WCDMA/CDMA all will get update based on Android Marshmallow 6 From Next Week (China ROM First )
then After testing Stable Update will be Released as per Process.