Windows 10 Technical Preview for Phones Released with 'Spartan'

The second public build of the Windows 10 technical preview for smartphones was released on Friday, bringing much broader device support and marking the phone debut of Microsoft's new "Spartan" browser.

Build 10051 is now available to "fast ring" Windows Phone users registered in Microsoft's Windows Insider program, according to Gabe Aul, chief of the Windows Insider program at Microsoft, in a blog post.

Aul actually revealed the timing of the release back in Wednesday's "Windows Weekly" podcast, hosted by longtime Microsoft reporters Paul Thurrott and Mary Jo Foley. Aul said in the podcast that the new build would arrive on Friday morning and would support "a significant number of new phones."

The number of supported devices was a bone of contention for Windows Phone users when the first technical preview was released in February. Only six low-end Lumia devices -- the Lumia 630, 635, 636, 638, 730 and 830 -- were supported in that build. At the time, Microsoft explained that it would not be able to support more devices until it finished developing a "partition stitching" feature that will enable higher-end phones to make room for in-place OS upgrades. The six supported devices already had "sufficiently sized OS partitions" to support upgrades, Microsoft had said.

On Friday, Aul announced that the partition stitching feature is now in the "main branch" of development, enabling the second technical preview to run on a much longer list of phones. The list of supported devices are:

  • "Lumia 1020
  • Lumia 1320
  • Lumia 1520
  • Lumia 520
  • Lumia 525
  • Lumia 526
  • Lumia 530
  • Lumia 530 Dual Sim
  • Lumia 535
  • Lumia 620
  • Lumia 625
  • Lumia 630
  • Lumia 630 Dual Sim
  • Lumia 635
  • Lumia 636
  • Lumia 638
  • Lumia 720
  • Lumia 730
  • Lumia 730 Dual SIM
  • Lumia 735
  • Lumia 810
  • Lumia 820
  • Lumia 822
  • Lumia 830
  • Lumia 920
  • Lumia 925
  • Lumia 928
  • Microsoft Lumia 430
  • Microsoft Lumia 435
  • Microsoft Lumia 435 Dual SIM
  • Microsoft Lumia 435 Dual SIM DTV
  • Microsoft Lumia 532
  • Microsoft Lumia 532 Dual SIM
  • Microsoft Lumia 640 Dual SIM
  • Microsoft Lumia 535 Dual SIM"

Microsoft is working to expand support to non-Lumia devices in future builds, Aul said. Also, certain devices, such as the 5-inch Lumia Icon, are still not supported because of what Aul described as a scaling issue that "makes the UI too small to be usable" on those phones. Microsoft is working to address the scaling issue for future builds.

Features and Bugs
The second technical preview includes both Internet Explorer 11 and, for the first time on phones, Microsoft's new "Project Spartan" browser. Designed for Windows 10, Spartan runs a new rendering engine called EdgeHTML that Microsoft says is better-suited to modern Web apps than IE, which is better for legacy apps. Spartan was included in the latest build of the Windows 10 technical preview for desktops, released in late March.

Microsoft intends to ship Windows 10 with both Spartan and IE 11, though Spartan will be the default browser. In the technical preview build released on Friday, however, Spartan is not the default browser. It is only an "early version" of Spartan, according to Aul. "For now, Project Spartan is not the default browser, and exists side-by-side with IE11," he said.

Other new features include:

  • Built-in Outlook Mail and Calendar apps
  • A new Phone app and a redesigned Messaging app
  • A redesigned contacts (People) app
  • The debut of the Maps app (preview)
  • Changes to the "app switcher" function

Aul also included a detailed list of bugs and missing features in the new technical preview build. For instance, automatic photo uploads from the Camera app to OneDrive may not work, and some settings from the first technical preview build may be lost. Text messages cannot be read over Bluetooth in this new build, Aul said.

Notably, Microsoft also removed its Office Hub feature from this build. "You won't be able to open Word, Excel, PowerPoint or OneNote files in this build. Preview versions of the universal Office apps will be available in the coming weeks," Aul said.

About the Author

Gladys Rama (@GladysRama3) is the editorial director of Converge360.