Microsoft announced further features of its planned Windows 10 platform, which CEO Satya Nadella said “marks the beginning of the more personal computing era in the mobile-first, cloud-first world” – with plans to offer it as a free upgrade for many existing Windows users.

Windows 10 will be available free-of-charge to Windows Phone 8.1 customers, as well as Windows 7 and Windows 8.1 users, who upgrade in the first year. While the company will lose licensing revenue as a result, it will help drive momentum for the new platform – something that was missing from the troubled Windows 8 rollout.

In a blog post, Terry Myerson, EVP of Microsoft’s operating systems group, said that there has also been a shift away from thinking of specific release of the platform separately, to “Windows as a Service”, with new features delivered as they are ready, and devices supported for their full lifetime with no extra costs.

“The idea of asking ‘What version are you on?’ will cease to make sense – which is great news for our Windows developers. With universal Windows apps that work across the entire device family, developers can build one app that targets the broadest range of devices – including the PC, tablet, phone, Xbox, the Internet of Things, and more,” he wrote.

At the heart of the new platform is the aim to offer a common feel across PCs, tablets, smartphones and other computing devices. “In this era, the mobility of the experience matters, not the mobility of the device, and the experience should work in a seamless, familiar way across devices,” the company wrote.

Windows10_Phone_Laptop-4C-500x285This means support for input methods beyond the current norms –“people should be able to naturally interact with technology as they interact with other people, with voice, gestures and gaze”. And protecting privacy will also play “a pivotal role in delivering trustworthy experiences”.

In line with this, Microsoft described Windows 10 as “the world’s first holographic computing platform”, including “a set of APIs that enable developers to create holographic experiences in the real world.”

“With Windows 10, holograms are Windows universal apps, and all Windows universal apps can also work as holograms – making it possible to place three-dimensional holograms in the physical world and enabling new ways to communicate, create and explore that are more personal and human,” it continued.

Among the developments revealed yesterday is that the Cortana voice assistant, which is already available on Windows Phone, will make its way to PCs and tablets; that a new browser is in the works, codenamed ‘Project Spartan’, which was “built with interoperability in mind”; Xbox features will be integrated with the platform; and universal Office apps will “deliver a touch-first experience across devices”.

The company also reiterated its ‘Continuum mode’, which will enable users to more easily move between keyboard and mouse and touch devices.

The next technical preview of Windows 10 for PCs will be available imminently, and for the first time on phones “later in February”. Myerson said that since Microsoft launched its Windows Insider programme in September, 1.7 million participants have delivered “over 800,000 pieces of feedback”.