Microsoft will map out its plans for the successor to Windows 8.1 – which might be named Windows 9 – at a company event in April, we're told.

Microsoft will start a discussion around the next iteration of its client operating system at its Build Conference on 2 to 4 April in San Francisco, California.

"Threshold", believed to be the code name for a wave of Microsoft updates which includes the newest client OS, is expected to start shipping a year later, in April 2015. The whole process will purportedly be similar to the Blue/Windows 8.1 update wave.

There’s no name for the client version of Threshold yet, but according to Windows blogger Paul Thurrott, the “current thinking” inside Microsoft is to go with Windows 9 – the idea being to distance the company and the client operating system from the experience that has been Windows 8/8.1.

Among the Windows features expected in Threshold are the long-awaited Start menu that was ripped from Windows 8 as part of the company’s march to tablets.

Also, MetroNotro – the touch interface that’s the signature of Windows 8/8.1 – will be updated.

It is expected that Metro apps – meaning those downloaded from the Windows Store – will be allowed to run on the classic Windows desktop.

Also, the Metro language is going to be fixed and "matured".

A Microsoft spokesperson told The Reg the company had "nothing share" on Threshold.

A very Terry Windows

All eyes will be on Threshold for a number of reasons.

It’ll be the first major release of Windows under operating systems group vice president Terry Myerson and since the massive Microsoft re-organisation intended to put devices first. Before the re-org, Myerson led the Windows Phone group.

There was Windows 8.1, of course, but work on this was already well under way by the time of re-organisation and Myerson's ascension in July last year.

The Threshold wave is expected to provide updates to all three Windows operating systems platforms: Windows, Windows Phone and Xbox One. The changes will see them share more elements and bring the operating systems closer together.

Threshold is significant for another reason, too, and this points to why the final name selected for the client will be so interesting.

Windows 8/8.1 does not appear to be being picked up by consumers or businesses. Microsoft lost a year on Windows 8 as OEMs didn’t deliver PCs or tabs, while consumers stayed away from machines as businesses upgraded to Windows 7 instead.

One reason for this is Metro, the hated interface that tore both users and devs away from the familiar desktop user experience and usual way of building apps.

The other was simply the small number of Windows 8 machines available to buy.

By 1 January, Windows 8/8.1 had scraped up just 13 per cent market share. In September 2013, the pair were on 10.19 per cent - and that was with early adopters using Windows 8.1, because this was the month before it was made generally available.

With this heritage, it’ll be interesting to see just how far Microsoft decides to go in breaking away from the Windows 8/8.1 nomenclature. ®