Microsoft has announced its Cortana service is being made available for Apple's iPhone and Android smartphones, although the tool will not have all the capabilities of Cortana on Microsoft's own Windows Phone platform.
The company detailed the move in a posting on the Windows blog, saying that it wants to extend the advantages of Cortana to more people by making a Cortana application available for Android and iPhone which works as a companion to Cortana on a Windows 10 PC.
In other words, Cortana for the iPhone or Android is being offered only to users of those devices who also have a PC and intend to upgrade to Windows 10.
There will also be limitations in Cortana's capabilities because these are non-Microsoft platforms, explained Joe Belfiore, corporate vice president of Microsoft's Operating Systems Group.
"Because it's ‘just an app' there will be certain things that Cortana does on Windows phones that won't work on Android devices or iPhones," he said.
"Some features require access to the system that aren't currently possible with iOS or Android, so things like toggling settings or opening apps won't initially be available in the Cortana companions for those platforms."
This means that Android and iPhone users will also not be able to invoke Cortana hands-free by saying 'Hey Cortana', as this requires low level access to the device's microphone, Belfiore added.
However, the Cortana app for iPhone or Android will support most of the other features of Cortana on the PC and Windows Phones, including context-sensitive alerts such as reminding the user to pick up milk the next time they are at the supermarket, for example.
Everything in Cortana's Notebook - the place where it keeps all the data it is tracking about the user - will show up across all devices, so that changes made on one device will be reflected when Cortana is used on a PC or other device.
The Cortana companion will be available for Android phones at the end of June and for iPhones later this year, Microsoft said.
However, users will also require a newly announced Phone Companion app (pictured above) on their Windows 10 PC in order to install Cortana onto a mobile device.
The Phone Companion app is intended to help users connect the Windows PC to a Windows phone, Android phone, or iPhone. It also extends to iPhone and Android smartphones the cloud-based synchronisation across devices that Microsoft offers on Windows platforms.
The upshot is that photos from a user's iPhone or Android handset will be automatically uploaded to a OneDrive account, and users will be able to access Office documents from their PC and stream tracks from their music playlist.
However, the Phone Companion app is not yet available, and is set to debut in an updated Windows 10 Technical Preview build coming in the next few weeks.
This also means that it will be available only for those signed up for the Windows Insider test programme until Windows 10 is released.
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