Internet Explorer in the Windows 10 Technical Preview for phones

Last year, we committed to the principle that the mobile web should just work for everyone, and introduced hundreds of targeted improvements to Internet Explorer in the Windows Phone 8.1 Update to dramatically improve interoperability with the mobile web. In November, we revealed the new rendering engine for Internet Explorer and Project Spartan on Windows 10, built on the same successful interoperability principles. Today, we’re excited to bring this new rendering engine to phones for the first time with the Windows 10 Technical Preview for phones.

In today’s preview build, the new rendering engine is hosted within Internet Explorer. Project Spartan, powered by the same new engine, will replace Internet Explorer on phones in a later preview.

What’s new in the Technical Preview for phones

For multiple releases, we’ve been committed to shipping a unified web platform for Windows devices across all form factors and screen sizes. As a result, the new Windows 10 web platform on phones comes with the same interoperability improvements, new features, increased performance, and improved standards support we’ve been previewing on PCs for the last several months. Going forward, you can expect to see an even tighter coordination of new web platform update availability on PCs and phones.

Windows 10 introduces a new user agent string for phones – based on our new desktop user agent string – designed to get the most modern, interoperable content for the mobile web. Sites inspecting the user agent string for analytics should be aware of the new string, but we continue to believe that feature detection rather than browser detection is the best solution for web developers writing interoperable content.

Mobile web and apps interoperable by default

The new rendering engine will be used for all web pages loaded in the browser on Windows 10 phones. Like on PCs, “x-ua-compatible” tags will no longer be supported to force older compatibility document modes. This ensures that sites on the mobile web will always get the latest, most interoperable engine.

Starting in Windows 10, Universal Apps powered by the new rendering engine will always use the latest update to the engine installed on the device. For application compatibility, Windows Phone 8.1 and earlier apps powered by WebBrowser or WebView controls will continue to be powered by the appropriate version of Trident.

Try it out and share your feedback

You can download the Windows 10 Technical Preview for phones today via the Windows Insider program, and share feedback directly with our engineering teams using the Windows Feedback app included in the preview. We also welcome feature requests and developer feedback via the Internet Explorer Platform Suggestion Box on UserVoice, @IEDevChat on Twitter, and in the comments below. We’re eager to hear your feedback and use it to make the mobile web a better experience for customers and developers alike!

— Kyle Pflug, Program Manager, Internet Explorer

Comments

• Anonymous
  February 12, 2015
  Very excited to see the news about the upcoming Windows 10 for phones. This post was the first one I've seen that explicitly stated that WP 8.1 apps will run on WP10. I've been trying to find documentation on the best means to update my apps written for WP 8.1 in Visual Studio Express 2012 for Windows Phone to Universal Apps, but I have not found the documentation explaining how to do so. At the very least these apps will still be available to users, even though they are not optimized.

• Anonymous
  February 12, 2015
  @Brian - we'll have more here and on the Windows blog about building apps for Windows 10 in the near future. Stay tuned!

• Anonymous
  February 12, 2015
  Really hoping for an improvement in stability with IE for WP10. Getting a bit tired of tabs crashing since 8.1 (especially with YouTube). Good luck guys

• Anonymous
  February 12, 2015
  Phone encryption will also support SD Card or internal memory only ?

• Anonymous
  February 12, 2015
  @Brian LePore: Running Windows Phone 8 and 8.1 apps, including Silverlight, has to be a prerequisite for Windows 10 for phones. WP7 apps should be supported if possible, I believe there are still numerous WP7 apps with no WP8 version (including things like the official Flickr app). To do otherwise would be to basically reset the store to zero, putting the platform way back behind competing platforms. Having the former Windows Phone chiefs in charge of Windows means, I think, that they are unlikely to repeat the error where Windows 8 (i.e. desktop/laptop/tablet) didn't run Windows Phone 7 apps, leaving an essentially empty store when Windows 8 released.

• Anonymous
  February 13, 2015
  How great would it be if Windows 10 on desktops actually could run Windows Phone 8 apps? :-)

• Anonymous
  February 13, 2015
  I am going to keep nagging until you remove the link "Exploring IE" from the links section to the right. This link leads to http://windowsteamblog.com which is DEAD. I am extremely dissapointed that this is now the third time I have to send the message. It reflects badly on how MS takes the clients that report errors serious.

• Anonymous
  February 13, 2015
  @ @ IE Blog - We're in the process of doing a major revamp of our blog including migrating to a new platform and as part of that we'll be renewing the sidebar links. In the meantime I'll see if I can get the outdated link fixed. Thanks for your feedback and sorry for the irritation!

• Anonymous
  February 13, 2015
  @Kyle - Ha! A similar system to that used by the Office blogs? That would be great!

• Anonymous
  February 13, 2015
  Hi

• Anonymous
  February 15, 2015
  Do you guys value memory leak bug reports at all? Other vendors consider them "mission critical" bugs. See connect.microsoft.com/.../breaking-issue-ie-11-11-0-9600-17031-freezes-on-right-clicking-the-page-for-context-menu. Whenever you release an update to IE11, I test this and get the same result. It started happening after first IE11 landed. In case you are wondering, I reported it via insider, blogs and connect. Happens on Windows 7, 8.1 and 10 (latest, greatest preview).

• Anonymous
  February 17, 2015
  The comment has been removed

• Anonymous
  February 17, 2015
  @ The Deeds - Good news! Looks like your bug is fixed in the new rendering engine in the latest previews of Windows 10. To enable the new engine, go to navigate to about:flags in Internet Explorer and set "Enable Experimental Web Platform Features" to "Enabled." This should fix the bug for you - if not, let me know and I'll look into it.