Microsoft has issued another build of the Windows 10 Technical Preview for phones, around two months since the last build was released.
The new version, Build 10051, is only being made available to members of the Fast release ring of the Windows Insider program for now, so you can bet it has a few rough edges.
The most striking difference between this build and previous ones, though, is that it supports lots more phones. Where February's build only supported six handsets, Build 10051 is available for no fewer than 33 models.
Among the supported mobes are Nokia and/or Microsoft Lumia models 430, 435, 435 Dual SIM, 435 Dual SIM DTV, 520, 525, 526, 530, 530 Dual SIM, 532, 532 Dual SIM, 535, 620, 625, 630, 630 Dual SIM, 635, 636, 638, 720, 730, 730 Dual SIM, 735, 810, 820, 822, 830, 920, 925, 928, 1020, 1320, and 1520.
The broad device support is thanks to a feature Microsoft has been working on called "partition stitching," which makes its public debut in this release. Many mobile operators ship Lumia phones with OS partitions that are too small to accommodate an in-place system upgrade; partition stitching compensates for that. Some models are still left out, though.
"Unfortunately there is an issue with scaling on certain devices (930, Icon, and 640XL) which makes the UI too small to be usable, and we need to add code to support new scaling thresholds for these devices," wrote Microsoft's Gabe Aul in a blog post. "That work is underway, so we expect to see support for them in the near future."
For those who can access this build, there are some important changes. Perhaps the most significant is that it includes a preview release of Project Spartan, Microsoft's next-gen browser that promises to do away with the web incompatibility woes caused by 20 years of Internet Explorer. Because Project Spartan is still in a raw state, however, IE11 remains the default.
The Messaging, People, and Phone apps have been updated with revamped UIs, as have Outlook Mail and Outlook Calendar. Outlook Mail can also now use Word for mail authoring, if fancy formatting is your thing.
There's also a new app switcher, and this release includes the first version of a new, unified Maps app that combines mapping data from both Bing Maps and Nokia's HERE Maps.
But you should never expect pre-release software to be perfect, and while this release fixes a number of bugs found in previous builds, the list of known issues is longer. Notably, the Office Hub has been removed in anticipation of the new Office Universal apps, meaning you won't be able to open Word, Excel, PowerPoint, or OneNote files on Build 10051.
You also can't talk to Cortana over Bluetooth, you can't enable flight mode (aka airplane mode), you can't filter calls or SMS messages, and you can't disable your data connection. Apps installed on SD cards might crash, incoming calls might not trigger a ringtone, and the Insider Hub might not launch, among other issues. And on phones with 512MB of memory, you can generally expect apps to crash at random, due to a memory management issue.
If none of that deters you, and you already have a phone running a preview build of Windows 10, by all means head for the Update & Recovery settings and check for phone updates. If this is the build that has convinced you to flash your Windows Phone 8 device, on the other hand, sign up for the Windows Insider program and read the instructions. ®