Microsoft released a new Windows 10 preview for phones today. It’s the second build for testers to try out. Among the new features are Project Spartan, an improved app switcher, and six new apps: Mail, Calendar, Phone, Messaging, People, and Maps.

Additions and improvements aside, this is a big deal because of the expanded list of compatible devices. The first preview (build 9941) worked on just six devices: the Lumia 630, Lumia 635, Lumia 636, Lumia 638, Lumia 730, and Lumia 830. But today’s build works on 35 devices.

Here’s the full list: 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, Lumia ICON, 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, and Microsoft Lumia 535 Dual SIM.

To get this new release, join the Windows Insider Program if you haven’t yet (registration). Get your phone set up and read the instructions carefully — you could brick your phone. If your handset is already on the Windows 10 Technical Preview, head to the Settings app, tap Update & recovery, then Phone update, and hit “check for updates.”

The biggest addition in this release is Project Spartan, its upcoming browser and replacement for Internet Explorer. You can find it in the All Apps list and pin it to your Start Screen.

Like on the desktop, Project Spartan uses Microsoft’s new Edge rendering engine. This build also includes early versions of Reading View and Reading List.

This has one controversial change worth pointing out: The address bar is on top, and a small actions bar is at the bottom. Many users have seen leaked screenshots and demanded that Microsoft keep the address bar at the bottom, where it is easier to access. The company says it is keeping this feedback in mind during development.

In Windows 10 for phones, Project Spartan is not set as the default browser and exists side-by-side with Internet Explorer 11. That said, Microsoft says it will remove IE altogether in a later build.

Spartan aside, Windows 10 for phones has improved the following apps:

  • Outlook Mail and Outlook Calendar: These are the new built-in mail and calendar universal apps for Windows 10. You can expect a new design, including a toggle to freely move between your email and calendar without returning to the Start screen. The apps connect to Office 365, Exchange, Outlook.com, Gmail, Google Calendar, Yahoo!, IMAP, POP, and other popular accounts.
  • Phone and Messaging: The Messaging app has a new visual design, and it lets you easily upgrade from a messaging conversation to a voice call with one click of the phone icon in the new app bar.
  • People: This is also a universal app, featuring a new visual design. It still shows you all your contacts across Exchange, Outlook.com, Gmail, Facebook, and so on.
  • Maps: The app includes the maps, aerial imagery, rich local search data, and voice-guided navigation experiences from both Bing Maps and Nokia’s Here maps. This is the first time the two have been integrated together into a single app.

With all these new apps, it makes sense that the App Switcher get an update as well. To see your recently used apps (the list now goes up to 15), just press and hold the back button on your phone. Support for landscape mode has been added when the app switcher is invoked from an app being viewed in landscape. Large phones now have a new grid layout for easily switching between apps.

Microsoft has also fixed a slew of issues in build 10051:

  • Keyboard layout: The keyboard now has period, comma, and emoji keys on the first page. Language switching is enabled by press-and-hold on the &123 key. You may also replace the emoji key with the language switching key.
  • Cortana: The icon resolution now scales with tile size.
  • Photos app: It no longer fails to launch periodically when attempting to add a photo attachment to an email, OneNote, or Facebook item. The tile will now pick up the phone’s theme color before it’s launched and start showing pictures from your collection, including OneDrive in the Live tile.
  • Microsoft Band: Now syncs with your phone after upgrading to Windows 10.

This is a massive Windows 10 for phones release, both in terms of features and the number of supported devices. That’s exactly what Microsoft needed, given all the complaints around the lack of new builds despite what was promised. Now the question is: can Microsoft release more than one build before its Build conference next month?