You'll soon be able to wake Siri with a simple voice trigger - even if your iPhone isn't plugged in to charge.

Apple will unveil its next iPhones during a San Francisco event in less than 24 hours, but that hasn't stopped the rumour mill from churning out some last-minute details about what's coming. 9to5Mac just claimed, for instance, the new iPhones will launch with an always-on "Hey Siri" feature.

We're not surprised because Apple's event invite teased the following: "Hey, Siri, give us a hint". The mere inclusion of "Hey Siri" on the actual invite made us wonder if an always-on, voice trigger feature was coming to iPhone. Plus, Google Now and other rivals already offer a similar feature.

Such a feature will allow you to say "Hey Siri" to activate Siri. It's considered an always-on feature only because your iPhone will always be listening for the "Hey Siri" voice trigger. This feature sort of existed on current and past iPhones, though those devices needed to be plugged in for it to work.

Keep in mind the new, always-on "Hey Siri" feature will not require the iPhone 6S and iPhone 6S Plus (rumoured names for the next iPhones) to be plugged in for it to work. But it's unclear if the feature is limited to the new iPhones.

Apart from that, 9to5Mac claimed Apple will debut an iPad Pro that starts at 32GB capacity for $799. Also, an updated Apple TV will be unveiled during the event, and it'll run a new iOS 9-based OS called "tvOS". - PAY MONTHLY PHONES Get the brand new Samsung Galaxy S9 and S9+ on the network that gives you 4G in more places than any other. EE runs the UK’s biggest and fastest mobile network, offering superfast 4G in more places than any other operator after pioneering the UK’s first superfast 4G mobile service in October 2012. The networks coverage extends to 90% of the UK’s landmass and EE has received extensive independent recognition, including being ranked the UK’s best overall network by RootMetrics.