The Mi 4 improves upon the discontinued Mi 3 in every aspect. It is thinner at 8.9mm and has a metal body with replaceable rear panels. It has a 5-inch full HD IPS display (no Gorilla Glass) along with a 13MP primary camera capable of recording 4k videos and 8MP front Sony stacked CMOS camera.  

Hardware specifications now include a quad core Qualcomm Snapdragon 801 processor, 3GB RAM, 64GB storage and a 3,080mAh battery.

According to Xiaomi, the battery would last one and a half day with normal usage and will offer quick charging, reaching 60 pc charge in an hour's time.

Other features include 8MP front camera, 3G, dual band WiFi, Bluetooth 4.0, USB host and radio.

Xiaomi also announced the availability of the MiUi 6 OS update. MiUi 6 comes with a revamped interface with new animations, motion graphics, flatter icons, smarter notifications and improved security features.

The firm has already sold over 1 million smartphones in India after it made an entry into the Indian market in July.