Apple has been forced to rush out an update to the latest version of its iOS operating system today after bugs left users with a number of problems, including one that could allow hackers to access contacts on locked phones.
The new operating system launched alongside the iPhone 11 and 11 Pro phones last week, bringing a new dark mode, redesigned Photos app, and security features reflecting the company's recent focus on privacy.
New iPhones have iOS 13 installed out of the box, while users with an iPhone 6S or newer can download it, but if you haven't updated yet you might want to wait a few days anyway.
Already a second update is on the way to add new features and address a number of flaws that made their way into the final version of the new operating system.
Many bugs had already been discovered in publicly released beta versions of iOS 13, including one that left users vulnerable to a hack that could see their contacts exposed, which Apple has known about since July.
The flaw was discovered by security researcher Jose Rodriguez, who reported it to Apple in July before posting a video of the hack on his YouTube channel earlier this month.
The video shows how hackers can access contacts by initiating a FaceTime call, rejecting it on the target device with a message response, then using Siri's voiceover function to bypass a passcode or biometric verification.
The security flaw exposes contact details, including addresses and phone numbers, but it does require hackers to have uninterrupted access to the device and can't be triggered remotely.
Apple had originally planned to release iOS 13.1 on September 30, but it has been moved up to today.
Time zone differences mean features might not start rolling out to Australian users until Wednesday.
Users who have updated to iOS 13 have already been reporting problems, including apps randomly crashing and the keyboard disappearing.
According to The Verge, iOS 13 is also littered with bugs causing dropped cell signals, a slowed down camera that gives photos the wrong date, and problems sharing files via AirDrop.
System updates have a spotted history for causing devices to slow down, leading to accusations of planned obsolescence targeted at getting users to upgrade to a newer device.
Last year, Italian authorities fined Apple and rival smartphone maker Samsung €5 million ($A8.1 million) each after finding the pair "implemented dishonest commercial practices" by failing to warn users about the performance impacts before they upgraded.
Apple was also fined a further €5 million for not giving consumers enough information about how to maintain and replace their phone's battery.
The company confessed in 2017 that it does slow down older phones by throttling their processor power to preserve battery, but argued the feature was designed to extend the life of older devices rather than prompt users to upgrade.
A similar throttling feature is coming to last year's iPhone XR and XS models with iOS 13.1, but the throttling is now optional and Apple is more upfront about when it is active.
Apple has included more advanced power monitoring hardware beginning with the iPhone 8 to help limit the need for performance throttling and maintain battery health.
The iPhone 11 models have a number of new features designed to make batteries last longer, including an option that uses machine learning to adapt to your routine and prevents fully charging your phone until shortly before you normally wake up and unplug it.