The primary selling point of Opera Mini, regardless of the version, was its server-side compression. Opera’s servers would fetch a webpage, compress it down to as little as 10% of its original size, and send it to the phone.

To understand the significance of Opera Mini 4.4, one must first understand the file format. is the application format for the MRE (Maui Runtime Environment) platform. MRE was developed by MediaTek to bring smartphone-like capabilities to low-end "feature phones" (like the itel, Tecno, and Nokia "banana" phones) that do not run Android or iOS.