What will Microsoft do with Windows 9? It's a question on many people's lips, and the rumour mill is going into overdrive with release dates, new features and more.

One thing's for certain: Microsoft is moving to a yearly cycle which means you're likely to see a new version of Windows every 12 months. The company already does this with Windows Phone and Windows RT needs regular updates to compete with Apple's iOS and Google's Android.

There are plenty of unknowns, however. Anyone who's used Windows 8, reviewed, for more than a few minutes will already know how unhappily the two sides of the OS co-exist. The traditional desktop doesn't really make sense on a tablet, while the Modern UI can go virtually unused on a desktop PC.

Eventually, Microsoft is likely to want to remove the old desktop and Windows 9 may be the platform on which it chooses to make the change.

Those who want or need to use applications that require the old desktop can stick with Windows 7 or even Windows 8. They won't be forced to upgrade, certainly not for a good few years (after all, consider how many people still use Windows XP!). and, by that time, who knows in what state the Modern UI will be.

Developers might have worked out how to make even the most complex apps touch-friendly, or we might end up with a separate business version of Windows where the keyboard and mouse remain king.

See also: Windows 9: How Microsoft might overhaul the interface in its next OS

Windows 9 could usher in a new pricing strategy, too. Apple has, for a while now, encouraged users to migrate to the latest version of Mac OS X with inexpensive upgrade prices and careful tweaks and feature upgrades. With iOS, updates are free.

It's possible that Windows 9 could be a free upgrade for Windows 8 owners, while Windows 7 users might have to pay to upgrade to Windows 8 first if they want to move to Windows 9.

Leaked builds of the so-called Windows Blue update hint at what we can expect from Windows 9.

The Start screen will be more customisable and easier to use. There's likely to be new gestures and possibly support for the Windows version of Kinect. Who knows: devices may even appear with Kinect built in (3D gestures should require only two webcams).

It also seems that Microsoft is addressing how two or more apps share the screen as the current 'snapping' is far too limiting, especially with bigger screens.

Crucially, though, Windows 9 tablets will need to be much cheaper. Apple and Google currently lead the way, offering a good range of tablets for under £400. The same can't be said of Microsoft.

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