MIUI 8 is the official Android-based application developed by Xiaomi for its smartphone system, while wechat is the smartphone application of Tencent's instant messaging tool. Therefore, as long as wechat supports Xiaomi mobile phones to run MIUI 8 system, then MIUI 8 can use wechat.
However, due to factors such as Android system version and phone configuration, some older versions of MIUI system may not be able to run the latest version of wechat application. If MIUI 8 does not support the latest version of wechat, then you may need to upgrade your MIUI system or download and install the latest version of wechat.
In 2021, miui8 can use wechat functions, but the version is slightly lower, and the current version is miui12