The recent discovery of documents from a 2007 lawsuit has revealed that Apple signed an exclusive five-year deal with US telecom service provider AT&T to sell the iPhone.
Apple and AT&T were targeted by a class action lawsuit filed in 2007, which accused the companies of not revealing the details of their contract.
The contract was first reported by USA Today in May 2007 but did not receive much public or media attention.
In court, Apple filed documents claiming that the deal had been made known to the public and the media, citing the USA Today article as evidence.
Technology blog Engadget salvaged the court documents filed by Apple to report on the validity of the five-year contract.
Recently there has been an increase in complaints from AT&T iPhone users who claim that the services offered by AT&T are failing to keep up with existing standards.
It is unclear whether the five-year contract between Apple and AT&T is still in effect.