iPhone users have ripped into Apple's latest update following claims that a system bug is rapidly draining battery life.

Complaints have taken Twitter by storm over the past few days with users alleging that the latest iOS 16.4 upgrade has diminished their iPhone's ability to hold charge.

One social media user said their device was now experiencing 'heating issues', while another added that their phone was failing to connect to Siri. 

'Is anyone else having over heating issues with their #iPhone after the latest updates? Battery won't hold a charge and now it says charging will resume when it cools down,' one tweeted.

Another added: 'After iOS 16.4 update the battery drains fast and Siri is having connection problem. Waiting for update as soon as possible to fix this issue.'

In addition to worsening battery, one user alleged that their device had completely slowed down since the update.

They tweeted: 'Pretty sure the latest ios update slowed down my iphone. It also made my phone die at 20% battery more often. 

'It's a 6S so like, relatively old (I'm pretty sure my high school nokia had a longer effective life...).'

iOS 16.4 was released by Apple just two days ago in an effort to fix bugs and boost security on iPhone 8 devices and later models.

It also introduced 21 new emoji including different coloured hearts, more animals and musical instruments. 

However, one Twitter user claimed that there is a 'known bug' on the iOS 16.2 - 16.4 updates which causes iPhones to have charging issues.

They alleged an Apple employee had told them this when their phone would not turn on while charging.

Although their iPhone 14 Pro Max was up and running again shortly, the Twitter user shared their hope for a 'bug' solution.

They tweeted: 'Apparently nothing was wrong, including the battery. 

Following recent battery life complaints, Apple Support was seen to invite some affected users to private Twitter discussions. 

To one user, they said: 'We'd like to help with the issue you are having with the battery on your iPhone. 

'Please meet us in DM with more details regarding what specifically changed after the iOS 16.4 update.'

While Apple has not yet commented on the issues, plummeting battery life can be quite normal following software updates such as these.

The changes triggered by power-intensive updates can take hours and even days to finalise, according to ZDNET.

Adrian Kingsley-Hughes, a researcher at ZDNet, explained: 'Installing a new OS on an iPhone triggers a lot of stuff to go on in the background, from indexing to recalibrating the battery, and this can go on for hours or even days.

'Not only does this consume power, but the battery recalibration can give the impression that the battery is draining more rapidly when in fact it isn't.

'Add to this the dual factor of a lot of app updates happening following a new release, combined with a lot of new features available that may put more drain on an older handset.'

If you're worried about your iPhone battery and it's been a few days since you updated to iOS 16.4, Mr Kingsley-Hughes advises checking your battery health.–Daily Mail