MICROSOFT'S UPCOMING Windows 10 Anniversary Update will see the firm shifting its attention to developers again, with the firm suggesting that many were put off by its not-so-practical 'write once, run anywhere' strategy.

The Windows 10 Anniversary Update of Microsoft's operating system is set to arrive at the end of July, one year after the platform's original release. It brings with it a major update to the code, delivering a number of enhancements, especially in areas such as the user interface.

One of the areas that's getting renewed attention is development, as Microsoft tries to convince programmers to start making broader use of the Universal Windows Platform (UWP) APIs introduced for Windows 10.

"As a company we've been trying to steer ourselves more in the direction that enables developers to really light up on top of Windows. It's a kind of refocus to make sure that developers are front and centre in the company," said Kevin Gallo, vice president of Microsoft's Windows Development organisation.

This approach is two-pronged, one aimed at building apps for Windows and one at using Windows as a core development platform itself, whether developers are building apps for Windows itself or for back-end services and websites. "Windows becomes the place to go and do your development," Gallo said.

Part of this involves giving developers the technology with which to innovate, including new capabilities such as integration with Cortana, enabling speech and Windows Ink for input.

However, another key new feature from Microsoft's point of view is the ability to bring traditional Windows applications into the Windows Store, which currently serves only new-style apps created using the UWP APIs. This is dubbed Project Centennial.

"Probably the biggest capability on the developer side is Project Centennial where we're allowing our Win32 developers, the faithful who have built for the platform and have great applications and want to bring them to the store, to do that as easily as possible," Gallo said.

This is not as straightforward as it sounds, as new-style apps are sandboxed to prevent them messing up the system through changes to the Windows Registry and other system files that typically happens when a traditional Windows app is installed.

For this reason, Project Centennial uses some form of application virtualisation, like the firm's App-V technology, that packages a Win32 app inside a sandbox with its own version of the registry and other dependencies.

Microsoft is making a Desktop App Converter tool available that takes a traditional Windows installation file, runs it inside an isolated Windows environment, and then captures the installation into an Appx file that can be distributed in the Windows Store.

However, another part of Centennial is making the UWP APIs in Windows 10 accessible to code created using Win32 or .Net, according to Gallo. Microsoft's position is that this will enable developers to gradually move to the newer APIs as they update their code over time.

"What we had before with Win32 applications and our Universal APIs is that they couldn't call them, so they had to rewrite their whole app. So with Centennial, they can get the best of both worlds - they can take their existing code and use it and put it in our Store, and then they can incrementally adopt all those new APIs, like for touch," he said.

But Gallo was at pains to point out that Microsoft has no plans to remove support for the Win32 API set from Windows any ime soon.

"I can't remember a time in the past when we have said that these apps will not work and we will not support them running on our future versions," Gallo said.

"With our Windows-as-a-service strategy, as we update it, sure, there are things that break, there are APIs that change behaviour and there are some issues we have to work on. But there's no time we're just going to turn off those desktop applications. There's no time we are going to just turn off Win32 apps."

However, some APIs, such as the Graphics Device Interface in desktop Windows, are not being included in the UWP API set. Again, this does not mean they are going away, Gallo said, just that they will not be included in non-PC devices such as phones, the Xbox or HoloLens, Microsoft's augmented reality platform.

Microsoft's UWP strategy was intended to attract developers by enabling a 'write-once, run anywhere' capability for apps with the Windows 10 platform, but the firm seems to realise that this is not entirely practical and is rowing back somewhat from this.

"I don't really think [users] want one experience that is identical across all devices, because that can lead to an average experience. What you really want to do is share a large percentage of code, especially the core business logic, and then tailor the user experience to each device form factor," Gallo explained.

One problem Microsoft faces is that the phone side of its platform represents just a tiny fraction of the smartphone market at around one per cent of handsets. This means that the UWP model is less attractive to developers than otherwise.

Whether developers will be tempted by the new APIs for features such as Windows Ink and Cortana in the Windows 10 Anniversary Update remains to be seen.