There is also speculation that Xiaomi will release a mini version of its next flagship model. Considering how high-spec'd the Mi4 will be, there is a good chance that a Mi4 mini might actually turn out to be a decent handset. Or perhaps a Xiaomi Mi4 mini will be similar to the Sony Xperia Z1 Compact, which shares many of its specs with the full sized model. The Xperia Z1 Compact has just a few changes, namely to the size and resolution of the screen, and the capacity of the battery.
Meanwhile, a published report out of China shows photographs of what is allegedly the housing for the Xiaomi Mi4. One of the photos shows both a micro SIM slot and a larger screen for the successor to the Xiaomi Mi3. You can take a look at the leaked housing for the phone by viewing the screenshot below. Since we are in the land of speculation here, take this report with a high degree of skepticism.
source: MyDrivers (Translated), gizChina (1), (2) via IntoMobile