The security update protects a raft of older iPhones and iPads from attacks linked to leaked hacking tools called DarkSword.

The American toy-making giant noted that it was continuing to "implement measures to secure its business operations," suggesting that the hackers may still be in the company's systems.

CareCloud, a major provider of medical records storage, said hackers accessed one of its repositories of patient data earlier in March. It provides technology for more than 45,000 providers covering millions of patients.

Demands for Apple customer records by federal agents in recent months underscore the privacy limitations of email.