The lawsuit, lodged in the US District Court in San Francisco, alleges that Apple ‘intentionally broke’ FaceTime apps running on 16 April 2016 in an effort to save money and encourage users of Apple handsets to upgrade to iOS7.

Included as evidence in the lawsuit are internal emails written by an Apple engineer which state unambiguously that the company ‘broke’ the conferencing capability on iOS6 in order to save on costs associated with using relay bandwidth.

Launched in 2010, the FaceTime app allows people to place video calls to other iOS users. Until 2012, the majority of calls placed through the app used a ‘peer-to-peer’ method of connection, which linked up devices directly to one another. However, in 2012 a jury found Apple’s peer-to-peer technology to be in violation of patents held by security company VirnetX.

As a result, Apple was ordered to switch all calls to a costlier ‘relay method’ which connects Apple devices via internet servers operated by a company called Akamai, rather than directly to one another.

The lawsuit reads: ‘Upon shifting 100 per cent of FaceTime call volume to the relay method, Apple’s relay usage soared. As a result, Apple began to incur multi-million dollar monthly charges for its use of Akamai’s servers.’

To fix the problem, the lawsuit alleges that Apple developed a new peer-to-peer connection method for connecting FaceTime calls – but ran into problems when Apple handset users refused to upgrade to iOS7 and thus to the updated version of FaceTime. Apple allegedly chose to break FaceTime for iOS6 in order to coerce the upgrades, rather than continuing to foot the bill for the version of FaceTime still reliant on relay servers.

The lawsuit is seeking undisclosed damages on behalf of iPhone 4 and iPhone 4s users, arguing that the company violated Californian competition law and caused harm to owners of older handsets that were ill-suited to running iOS7.

Sources: Fortune; BGR