Microsoft's chief marketing officer and chief financial officer Tami Reller has revealed that more than 100 million licences for Windows 8 have now been taken up across a wide range of devices, from Notebooks and desktop PCs to tablets.

Speaking to Microsoft's own blog, Reller explained that the figure included new kit that shipped with the operating system pre-installed and upgrades. It marks a 40 per cent rise in total Windows 8 devices since January. "We recently surpassed the 100 million licences sold mark for Windows 8," she said.

"This number includes Windows licences that ship on a new tablet or PC, as well as upgrades to Windows 8. This is up from the 60 million licence number we provided in January. We’ve also seen the number of certified devices for Windows 8 and Window RT grow to 2,400 devices, and we’re seeing more and more touch devices in the mix."

Next up for Windows 8 is the Windows 8.1 update, codenamed Windows Blue. Reller revealed that it is still planned for release in 2013, and that it will bring a host of new features to the platform. "Windows Blue is a codename for an update that will be available later this year, building on the bold vision set forward with Windows 8 to deliver the next generation of tablets and PCs," she said.

"It will deliver the latest new innovations across an increasingly broad array of form factors of all sizes, display, battery life and performance, while creating new opportunities for our ecosystem. It will provide more options for businesses, and give consumers more options for work and play.

"The Windows Blue update is also an opportunity for us to respond to the customer feedback that we’ve been closely listening to since the launch of Windows 8 and Windows RT. From a company-wide perspective, Windows Blue is part of a broader effort to advance our devices and services for Microsoft."

Microsoft is heavily tipped to reveal smaller Surface tablets during its Build Developer Conference at the end of June. What's the betting that it will use that occasion to also unveil more on Blue?