Apple Inc.'s MFi Program, referring to "Made for iPhone/iPod/iPad", is a licensing program for developers of hardware and software peripherals that work with Apple's iPod, iPad and iPhone. The name is a shortened version of the long-form Made for iPod, the original program that ultimately became MFi.
The MFi program covers various device connectors including the headphone jack, original dock connector and the newer Lightning connector, as well as AirPlay support. Companies joining the MFi program and passing certification tests are able to display certain MFi-related logos on their product packaging, like the "Made for iPod" badge.
With the introduction of the Lightning connector the branding was changed and officially became MFi, a term that had been used unofficially for some time. Lightning also introduced additional protocols that could only be officially supported through the MFi program. In addition to the technical requirements, according to TUAW, Apple also took the opportunity to update the licensing agreement to require all 3rd parties to agree to Apple's supplier responsibility code.