Windows Blue will be a free update -

Microsoft has announced that its coming Windows Blue, or Windows 8.1, will be delivered as a free update through the operating system's app store.

Redmond's chief marketing officer, Tami Reller, told JP Morgan's Technology, Media and Telecom Conference in Boston that Windows 8.1 will be delivered free to Windows 8 and Windows RT users.

She said that the update will be "easy to get from the Windows start screen through the app store," so that punters who have Windows 8 or plan to buy a device in the near future can get the Windows 8.1 fairly easily.

Of course she did not say when Windows 8.1 would become available but hinted that Vole was "very sensitive to the timing of the holidays".

The hint means that Vole will provide devices with Windows 8.1 pre-loaded in time for the holiday 2013 season, but those who purchase a Windows 8 device later this year will be able to easily upgrade to 8.1.

Microsoft will release a public preview of Windows 8.1 at the Build conference. After 26 June, the preview will be available for anyone to download, Reller said.

It looks like Vole will be expanding the allowable size of tiles that one can place on Windows 8's Start Screen, and adding customisation options, among other things. Microsoft will bring back the start button.

Microsoft has been rolling out small updates via Windows Update since the October launch of Windows 8, but hinted that Windows 8.1 will be "more substantial" than anything Redmond could deliver via daily or weekly updates, Reller said.

Windows 8 users will be told when Windows 8.1 is live, she added.