The FBI asked Apple to create a version of iOS that would both disable passcode security features and allow passcodes to be entered electronically, allowing it to then brute force the passcode on the device.
Apple announced that it would oppose the order in an open letter penned by Tim Cook, who said the FBI's request would set a "dangerous precedent" with serious implications for the future of smartphone encryption. Apple said the software the FBI asked for could serve as a "master key" able to be used to get information from any iPhone or iPad - including its most recent devices - while the FBI claimed it only wanted access to a single iPhone.
Apple's dispute with the FBI ended on March 28, 2016 after the government found an alternate way to access the data on the iPhone through the help of Israeli firm Cellebrite and withdrew the lawsuit.