Apple announced Wednesday that it would block access to a port that law enforcement uses to crack into iPhones during criminal investigations, a move that could reignite debate over whether tech companies are doing enough to help authorities investigating serious crimes.Apple said the change, which would disable the Lightning port on the bottom edge of iPhones an hour after users lock their phones, is part of a security upgrade to better protect the private information of iPhone users. It will have little practical effect on most people using the devices but will make it far more difficult for investigators to use extraction tools that attach through the port for the purpose of collecting the contents of seized iPhones.The change isnít intended to thwart law enforcement efforts, Apple said. "Weíre constantly strengthening the security protections in every Apple product to help customers defend against hackers, identity thieves and intrusions into their personal data," said the company in a statement. "We have the greatest respect for law enforcement, and we donít design our security improvements to frustrate their efforts to do their jobs."Yet some authorities almost certainly will see it as yet another barrier to carrying out their legally sanctioned investigations.Apple has been at the center of such debates since it declined FBI requests to unlock an iPhone 5C used by a gunman in the San Bernardino, Calif., shooting in 2015 that left 14 people dead. A brewing legal showdown was defused after the FBI hired professional hackers to crack into the device. Many such efforts rely on gaining access through the Lightning port for which Apple is now restricting access.The Lightning port is used for charging iPhones, which will still be possible when the devices are in their locked state, and for transferring data, which will be blocked after an hour. The change is coming through a series of software updates and should be on most iPhones sometime in the fall.