There's a new fast ring build of Windows 10. As ever, the new build mixes features and fixes.

The fix I'm most happy to see (and yet, strangely disappointed by) is that the Start menu is less broken than it is in Windows 10. As I noted in my Windows 10 review, Windows 10's Start menu has an unfortunate hard-coded limit; more than about 500 items on the Start menu (any mix of Start menu entries and live tiles) and Windows would stop adding more. This would make it impossible to launch applications through the Start menu; even the search feature wouldn't find them. The new insider build lifts the limit to 2048. This makes it much less likely to be reached in normal use, though it's still not clear to us why there's any artificial limitation at all.

The new build also offers new tile arrangement options, allowing for wider columns that can fit more tiles.

Tablet view has a pretty nice improvement, too; from the task view that gives an Exposé-like view of all runnings apps, you can now pick up one of the thumbnails and drag it directly to the side of the screen to snap it.

The restrictions on Cortana have also been slightly relaxed. Currently, to use Cortana you have to sign in to Windows with a Microsoft account. In the new build, that's no longer the case. A regular local account is enough. This is not to say that Cortana doesn't need a Microsoft account—if you turn her on, she'll require you to sign in as part of her setup process—but the operating system-wide Microsoft account integration is no longer needed. In turn, this somewhat reduces the privacy impact of using Cortana.

The Edge browser also includes a significant few feature: support for the Object RTC API. There are two RTC ("Real Time Communication") APIs, both designed to enable real-time audio and visual communication apps to be built directly in the browser. Chrome and Firefox both implement the earlier WebRTC API. Microsoft, however, hasn't, with the company arguing that for various technical reasons it's a bad spec that's ill-suited to a browser-based JavaScript API. Object RTC is a different API design that Microsoft (and others) feel is a more appropriate design that's better equipped to handle important situations such as changing amounts of available bandwidth and simulcasting, and it is set to become an integrated part of WebRTC version 1.1.

The Skype team has outlined their plans for using both WebRTC and ORTC to enable browser-based Skype clients that don't need any plugins. This work includes multiple portions. The Skype clients are being altered to use a range of standard transport protocols; the same family of standard protocols that RTC use. Microsoft is also adding additional codecs to Skype. Skype currently uses a particular subset of the H.264 video protocol for its video known as 264UC. Skype is being extended to use H.264, which is currently available in Firefox's WebRTC implementation, and will soon be available in Chrome. Similarly, Microsoft is adding support for the Opus audio codec to the full range of Skype clients.

The purpose of this work will be to allow Skype and the browsers to communicate directly. In the interim, it looks as if Microsoft intends to use a relay service to bridge the gap between Skype, Edge, and Skype for Business (all natively using 264UC) and Chrome and Firefox (using H.264).

The company is going to roll out the first iteration of plugin-free Skype later this year. This will use ORTC in Edge, and WebRTC in Chrome and Firefox.

As ever, there are a few known issues with this build. They're all listed on Microsoft's blog, but one of them is a little strange; opening files in Notepad at the command-line won't work if you just use a bare filename. If you use a filename with a path (even a partial path) it will work. It's hard to imagine how such a thing might have broken, but then again, that's the kind of weirdness that you're expected to live with if you're using the Insider previews.