Last fall, 911 emergency-response service centers in a dozen states were the victims of a massive cyberattack that resulted in hundreds, if not thousands, of iPhones repeatedly calling 911 without the knowledge or direction of owners. Nearly five months later, Apple say it has fixed the apparent flaw that made the attack possible. 

The Wall Street Journal reports that Apple’s latest iOS update — iOS 10.3 — is aimed at preventing similar cyberattacks from happening in the future.

The October incident, which lasted for nearly 12 hours and affected call centers across the country, was allegedly caused when an 18-year-old wrote code that exploited a feature in iOS devices that allowed users to click on a phone number and immediately make a call.

While the total number of calls received isn’t known, many of the centers reported receiving hundreds more than they would on a normal day.

For example, the Journal has previously reported that a center in Surprise, AZ, fielded 174 calls in just one hour. The same time the day before only yielded 24 calls.

Apple tells the WSJ that it first began working on the issue with app developers, asking them to remove the capability.

The new update, according to the tech giant, completely removes that capability from apps and requires users to provide a second confirmation that they actually want to place a call.

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