If you're wondering if your iPhone's battery has been running out more quickly since you downloaded iOS 11, you're not alone.
Researchers have found that the initial release of iOS 11 drains iPhone batteries more than twice as fast as the previous operating system iOS 10.
The analysis from mobile security company Wandera claimed the average battery decay for an iPhone running iOS 10 under constant use is 240 minutes. For devices that have upgraded to iOS 11, the decay time is just 96 minutes. However, recent patches to iOS 11 appear to have limited the battery drain.
Wandera analysed the battery decay of 50,000 iPhones and iPads on its network that were used moderately to heavily. It compared the average battery drain over three days and estimated the average.
A drop in battery life is fairly common on older devices that upgrade, since new operating systems often use more power than previous ones. They also have early bugs that are fixed in subsequent releases. But the problem with iOS 11, designed for the iPhone 8 and iPhone X, has been notable among many users.
The findings appear to explain why so many iPhone owners have flooded social media with complaints since the release of iOS 11.
"It is a simple reality of software: there will always be bugs in new major OS releases, which are constantly pushing the limits of the devices they are running on," said Matt Vlasach, director of product at Wandera. "This, in turn, burns battery and always causes a new uproar about battery performance.
"It is inevitable that these problems will be addressed and improved as time goes on, until the next major update."
Apple has released two updates to iOS 11 since it was first made available on September 19. The first update, iOS 11.0.1, went some way to fixing the battery problems, according to Wandera. The analysis showed a 65 per cent improvement in the update, with a battery decay time of 159 minutes, as opposed to 96 minutes.
The second, iOS 11.0.2 was released earlier this week and it is too early to tell if this has had another effect.
Other problems users commonly have when updating their software is that some apps stop working and older models are no longer supported.
Apple customers who are unsatisfied with their battery life can take a number of steps to help it last longer. These include turning off auto-brightness, found in Settings -Accessibility - Display Accommodations; and background app refresh, found in Settings - General.
Switching off location services for apps that don't require it can also help preserve battery, as can activating low power mode.
Apple advises users to upgrade to the latest versions of the software, despite the complaints. It is constantly looking for ways to improve how its systems work.
"If you find the battery drain on iOS 11 too much to tolerate, you might start thinking about a switching back to iOS 10.3.3," said Wandera.
"While this may be tempting, we strongly advise against it. The more up to date your software, the more protected you are from hackers attempting to exploit your device and infiltrate your personal and corporate data."