Σgradually available for its newer models is the Stable MIUI 10 ROM of Xiaomi, with the Mi 8 SE and Mi Mix 2 have begun to receive it gradually according to information from China.
As it became known, this is the Chinese version of MIUI 10, which is available in both models with build numbers. 10.0.1.0.OEBCNFH and 10.0.0.1.0.ODECNFH respectively for the Mi 8 SE and Mi Mix 2. Of particular importance is the size of the two ROM's with the first being 930MB and the second just 630MB.
Once the Chinese ROM is available, it's only a matter of time before the Global ROM (MIUI 10) starts upgrading, so if you own both devices, it's a good idea to get ready to upgrade in the next few days. You can find out all the relevant information in the MIUI Forums of course.