The last few developer betas have used USB Restricted Mode, but this is the first time Apple has included it in a final build of iOS. The port will still function after the update, but will shut off data an hour after a phone is locked if the correct password is not entered.
The change may not sound like much, but it probably throws a serious roadblock in law enforcement attempts to break into iPhones.
"We are continuously strengthening protection in every Apple product to help customers protect themselves from hackers, identity thieves and intrusions into personal data".
A cryptography professor notes that Apple is fixing a huge security vulnerability, because these Grayshift devices could easily get out into the public and be used for purposes other than law enforcement.
Last November, the Federal Bureau of Investigation did not seek Apple's help in cracking open the locked iPhone of Devin Kelley, who shot and killed 26 people in a Sutherland Springs, Texas church, in the critical first 48 hours after recovery.
Jack Gold, principal analyst with J. Gold Associates, said Apple wants its mobile devices to be viewed as the most secure in the industry.
Doing so would render the port useless to law enforcement agencies, which crack encrypted iPhones by plugging them into special phone-unlocking devices.
"At Apple, we put the customer at the center of everything we design". Subsequently, another company, US startup Grayshift, earlier this year also began touting its ability to unlock iPhones to law enforcement with its $15,000 GrayKey tool, according to media reports.
Refuting the FBI's claim, Apple said it reached out to the bureau "immediately" to offer assistance in getting into the gunman's iPhone and expedite its response to any legal process. In April this year, Motherboard had reported how GrayKey was a cheap tool for bypassing the iPhone's security, which was being used by police in the US. Several companies provide similar services to unlock iPhones.
Opening locked iPhones through these methods has become more common, law enforcement officials said.
"They are blatantly protecting criminal activity, and only under the guise of privacy for their clients", Moore told the Times.
The encryption on smartphones only applies to data stored exclusively on the phone. Apple said that since 2013, it has responded to more than 55,000 requests from the United States government seeking information about more than 208,000 devices, accounts or financial identifiers.