All the news from Microsoft's 2013 Build developer conference

For four years now, Microsoft has been telling us that the future would be Windows, running across "three screens and a cloud." Now that Windows 8, Windows Phone, and the Xbox One are all being built on top of the same common core, we expected the company would have more to share about the realization of that vision at this week's Build developer conference. Developers need to know how to create, port, and publish apps and games across all three platforms, and Microsoft needs those developers to give its new platforms momentum and staying power. At Build, we were particularly optimistic to hear whether the Xbox One and Windows PCs might share code.

Unfortunately, Xbox has no real presence here at Build. It's on display on the show floor, but it's under lock and key with a dedicated security guard. There are no developer sessions devoted to creating Windows apps or games that could appear on Xbox One, or that address whether the Xbox and Windows might share a store. Microsoft employees we approached couldn't speak to how these things might work. Even sessions with promising names like "Beautiful Apps at Any Size on Any Screen" were completely focused on computer screens, not televisions. And though the Xbox One's new Kinect sensor is now coming to Windows computers, there was no suggestion that the peripheral would necessarily allow the Xbox and a Windows computer to play the same games this time around.

Microsoft might not be ready to talk about Windows Phone updates at Build, but that hasn't stopped the company from showing off a wall of 200 phones running its mobile operating system. The display was built by Windows Phone developer Rudy Huyn, and it contains 200 Lumia 825 developer devices that can be controlled remotely. Huyn helped build an app that powers the interactive display that demonstrates the Windows Phone interface and Nokia Maps. All the devices simply sit mounted on the wall waiting for a signal from a custom Windows Phone app. We've seen similar efforts on other devices before, but this impressive display is the first time you'll see 200 Lumias in such close proximity.

Leading up to Microsoft's Build developer conference there were a number of rumors related to a possible Surface announcement. Now that both keynotes are over it's clear there's no new 7- or 8-inch Surface tablet or a refreshed Haswell Surface Pro. However, Microsoft appears to be dropping some accidental hints at the future of Surface and other 7- and 8-inch tablets.

In a session today at Build, on building apps across multiple screen sizes, Microsoft showed off some of the anticipated screen sizes for small Windows 8.1-powered tablets. Although the list, used in the company's developer tools for testing, wasn't exhaustive, one particular resolution and screen size caught our eye: a 10.6-inch display running at 2560 x 1440. Microsoft's Surface Pro tablet includes a 10.6-inch display with a 1920 x 1080 resolution, a screen size also listed in Microsoft's tools. The inclusion of a higher resolution is surprising as the 10.6-inch screen isn't a size that's used widely by other PC makers. Most have standardized around 13.3-inch and 11.6-inch panels for laptops and tablets, with a variety of other non-standard sizes outside of that. Microsoft didn't detail which manufacturers would create 10.6-inch devices, but given the limited use of that display it's possible the company has accidentally revealed a high-resolution Surface.

Microsoft's Build developers conference in San Francisco has mainly focused on Windows 8.1 so far, but the company spent a few minutes talking about the future Xbox One development platform on Thursday. Steve Guggenheimer, vice president of Microsoft's Developer and Platform Evangelism group, provided big hints at how developers can target the Xbox One in the future. "Xbox one has two engines, it's got a gaming engine and it essentially has a Windows 8 engine," said Guggenheimer, referring to the new Xbox One architecture that lets the next-generation console run on the Windows 8 kernel.

Guggenheimer demonstrated remote debugging of a basic web application that appeared to be running on an Xbox One, noting that the app included an xbox.js library. "Nothing to announce today, but when I talk about that common core you're seeing that common core in action, being able to target other devices devices over time that run the Windows 8 engine," said Guggenheimer. He then proceeded to tease developers by encouraging them to develop Windows 8 apps in order to build Xbox One apps. "If you want to know about how to get a head start about thinking about developing for Xbox One, the logical thing to do is go build Windows 8 applications," said Guggenheimer.

Check-in service Foursquare is apparently showing off its first native tablet app today, and it's for Windows 8. The Next Web reports that at the Build conference today, Foursquare announced an app specifically designed for Windows 8 tablets. Little more is known about it, but the app fits with Microsoft's coming focus on small Windows tablets, which Steve Ballmer said yesterday would be massively scaled up in the coming months. Checking in on a full-sized Surface (or iPad) may not be the kind of experience Foursquare originally had in mind for its app, but an 8-inch device can be easily pulled out at a restaurant.

Acer's Iconia W3, an 8-inch tablet given free to all Build attendees, is a gift horse whose teeth are hard to ignore. It's surprisingly heavy, a little unwieldy, and the 8-inch screen is extremely poor. Still, that 1280 x 800 screen and Atom processor let us check out how the Windows 8.1 Preview runs on smaller tablets, and the results are actually pretty good. It's the same interface you'd expect, only small enough to fit in a purse and with some important tweaks on top.

Microsoft has focused on Windows 8.1 this week at its Build developers conference, but the company has a few sessions on Windows Phone too. Speaking to The Verge on Wednesday, senior Windows Phone product manager Larry Lieberman outlined the company's perspective on Windows Phone 8's progression. "We think we're solidly the third ecosystem right now," says Lieberman. "That's a huge announcement in some respects." In fact Windows Phone overtook BlackBerry in May, but it's still very much a two-horse race with Android and iOS dominating.

Lieberman isn't worried about BlackBerry though. "I don't think they can bring to the table some of the things we have," he says. "The fact like we're delivering across such a different set of price points to such a large audience." These low price points have been a key part of Nokia's influence on the Windows Phone platform, with the pair teaming up to push the OS software down to low-cost devices. Microsoft isn't comfortable in third place though, and Lieberman believes Windows Phone is "growing faster than anyone else right now."

Windows RT was largely unmentioned during Microsoft's Build opening keynote on Wednesday, but the company is also releasing a preview version of Windows RT 8.1 this week. Designed to update ARM-based tablets to the same features that Windows 8.1 provides, there's little difference between the two. I got the chance to run Windows RT 8.1 on a Surface RT and see exactly what Microsoft has improved.

First things first, the desktop mode remains. Despite not being able to install and run traditional desktop applications, the desktop mode in Windows RT 8.1 is still present and includes the Start button just like its x86 counterpart. It's not that surprising given Microsoft's stance with Windows RT, but it's clear the company is continuing to develop both operating systems alongside each other.

If you’re ready to bring back the Start button, you can head over to Microsoft's website to download the Windows 8.1 Preview right now. The Preview release is open to all users, though any machine that isn't running Windows 7 or later will have to perform a fresh install to get it working. For those already on Windows 8, Microsoft is offering the 8.1 Preview directly through the Windows Store. To access it, users have to first visit Microsoft's website to initiate a small update to Windows itself. Afterward, their device will restart and direct them to a download of the 8.1 Preview update.

Update: Microsoft has opened the Windows 8.1 Preview up to all users. This article has been updated to reflect the additional availability.

Microsoft is opening up pre-orders for development kits of its next-generation Kinect for Windows. The new peripheral, which was unveiled at the Xbox One launch in May, features a vastly improved sensor set and microphone array that can recognize movements and people with greater accuracy and in larger numbers. Starting today, developers can sign up for a development kit that will include a pre-release version of the new Kinect, early access to a new SDK, and the final product when it's ready. The price is set at $399, but not everyone ordering is guaranteed a kit — Microsoft will pick successful developers after registration closes on July 31st.

Along with the launch of the new Kinect for Windows, Microsoft has also detailed the capabilities of its new SDK, version 1.8. New features include real-time background removal, which lets you isolate a person away from their surroundings, faster Kinect Fusion scanning with better color capture, and the ability to create Kinect for Windows apps using HTML5 / JavaScript. The SDK will be released in September; hopefully we'll see Windows developers take full advantage of the improvements to create more realistic and intuitive cross-dressing applications soon.

Microsoft's Windows 8 operating system is about to get some big name apps: Facebook and Flipboard. During a private session at Build on the upcoming Windows 8.1 update, Microsoft revealed the existence of both applications on an 8-inch Acer device. A company spokesperson confirmed to The Verge that the apps are official and coming to Windows 8, and Steve Ballmer announced both apps onstage at Build today. Speaking about Facebook, the CEO said the social network has long focused on connecting people across all platforms and the new app "is an exciting way to enhance that vision." Unfortunately he provided no details on when we can expect Facebook.

Flipboard has also published a blog post with a bit more information on its upcoming Windows 8 app, saying that it "will be custom-made for this new platform." A new nine-second teaser video gives us our first look at Flipboard for Windows 8, which is far more than a port of the iPad version: it appears to embrace the Windows 8 experience quite well. The company promises more information closer to launch, which will be later this year.

Microsoft is teasing a version of Office designed specifically for Windows 8.1 this week at Build. In a private session ahead of the conference, the software maker briefly showed a copy of PowerPoint running in the "Metro" mode of Windows 8. Microsoft currently ships desktop versions of Office for Windows 8, but the company has only released OneNote as a Windows 8-style app so far.

At its Build keynote today, graphics-intensive transitions and videos inside of presentations were demonstrated using the new "Metro"-styled PowerPoint. The company's Julie Larson-Green said that "all of this works on ARM and x86... from the smallest, tiniest tablet to the largest, most powerful workstation," adding that this "really shows the power of what you can do in Windows RT."

The Surface Pro, Lenovo ThinkPad Helix, Toshiba Kirabook, Dell XPS 12, and many other high-end Windows 8 machines suffer from the same nasty flaw: even as their high-resolution touchscreens are crisp and beautiful, the user interface is often too small. Text can be hard to read and touchscreen buttons extremely difficult to touch. That could all change soon, though. Windows 8.1 will add support for high-density displays, finally scaling the user interface to these increasingly high-quality devices.

Microsoft is taking over San Francisco's Moscone Center today to introduce a preview version of Windows 8.1. Although the company has revealed most of the features in the upcoming update to Windows 8, I’ve had a chance to get well acquainted with the Windows 8.1 preview to learn more about the changes involved.

In my previous look at 8.1 I summarized that the preview brings many small tweaks that make for a significant update, and that still stands. Microsoft is pushing a new search experience alongside UI tweaks, new and improved apps, and some better customization options for regular and power users alike. Let's dig in.