The operating system will take up a 1.3GB of space to install on the device. iOS 8 required more than 4GB, which caused issues for users requiring them to delete apps.

The new search assistant that is an advance on Apple's Spotlight search facility, integrates with Siri to create a Google Now competitor, capable of displaying data from apps and the web, and controlled via text or voice.

Siri can now offer directions based on invitations pulled automatically from email and leave reminders for the events.

The information displayed is context sensitive, including the ability to understand that the user is looking at something in particular when they say "remind me about this later today". Users can plug in headphones in one location and always get the music app, for instance.

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