Microsoft is taking an important step towards helping businesses stay up to date with the latest software, services, and devices. Enterprise Mode for Internet Explorer 11, announced today as an update for Windows 7 and Windows 8.1, provides better compatibility for older versions of Internet Explorer and tools to manage which Web apps use it.

Businesses can benefit from the modern Web standards, better performance, and increased security of our latest browser, while extending existing investments in legacy Web apps. And by decreasing dependencies on older versions, Internet Explorer is helping customers stay up-to-date with Windows 8.1, services like Office 365, and devices like the Surface Pro 2.
How does Enterprise Mode help you stay up-to-date?

Many businesses are experiencing tension between today’s Web apps and services—which may require modern standards like HTML5 and CSS3—and older Web apps and services, designed for older versions of Internet Explorer. Legacy apps often represent a significant investment and have long, multi-year lifecycles, effectively making these customers dependent on an older version of Internet Explorer until they can upgrade these Web apps to modern Web standards.
Introduced in 2009, Internet Explorer 8 was the first browser available on Windows 7 and included innovative features like Compatibility View for older Web sites. Because it also ran on Windows XP, many customers and developers chose to standardize on Internet Explorer 8 to help ease the migration to Windows 7. According to Net Applications, Internet Explorer 8 still has more than 20% of the desktop browser market share; despite the fact that IE9, IE10, and IE11 have superseded IE8, many customers still rely on Internet Explorer 8 to run their business.
By providing better backward compatibility for Internet Explorer 8, Internet Explorer 11 with Enterprise Mode is intended to help break this dependency and provide the best of both worlds: A modern, up-to-date browser that helps customers extend their existing investments in older Web apps.
How does Enterprise Mode provide better compatibility?

In designing Enterprise Mode for Internet Explorer 11, engineering reviewed compatibility problems reported by customers and found clusters of similar issues. Some of the areas targeted by Enterprise Mode include:

  • User agent string differences. Many legacy Web apps use browser detection, not today’s best practice of feature detection. By replicating the original Internet Explorer 8 user agent string, Enterprise Mode works for sites that fail if they can’t recognize IE8 as the browser.
  • ActiveX controls and other binaries. Some ActiveX controls silently fail if they query the browser version and get a response they don’t expect, so Enterprise Mode appeases these by mimicking IE8’s responses. In testing, customers report that many of these ActiveX controls “just work” in Enterprise Mode.
  • Deprecated functionality. Internet Explorer 8 still contained some vestiges of proprietary functionality, such as CSS Expressions which was used to place objects dynamically on a page. This functionality was removed in later versions of Internet Explorer, but some legacy Web apps used this to place buttons and other elements. Enterprise Mode brings back some deprecated features, including CSS Expressions.

A Web app works properly when viewed in Internet Explorer 11 with Enterprise Mode on the right. Note the Enterprise Mode icon, circled in the address bar.
  • Pre-caching and pre-rendering. Many modern browsers like Internet Explorer 11 pre-cache and pre-render pages, to make browsing more fluid. When you click on a pre-cached link, one tab disappears while the pre-rendered content tab appears in its place. To a legacy navigation controls, this behavior is confusing—so Enterprise Mode turns it off.

When Internet Explorer 11 renders a page in Enterprise Mode, numerous configuration and code changes eliminate common compatibility issues in these and other areas. Also, by targeting Internet Explorer 8—and IE8’s Compatibility View—Enterprise Mode also provides some benefit for sites designed for even older versions, such as Internet Explorer 7. This is emulation, not virtualization; Enterprise Mode provides a better emulation of IE8 within IE11, while avoiding many performance, security, and other problems associated with running older Internet Explorer 8 binaries.
Speaking of performance, we’ve made a lot of browser improvements in the last five years; Internet Explorer 11 is dramatically faster than Internet Explorer 8. Web apps load twice as fast, and Enterprise Mode takes advantage of network improvements, redesigned script and layout engines, and hardware-accelerated graphics. While we believe that real-world performance matters when evaluating a browser, the JavaScript benchmark results below highlight the significant difference between Internet Explorer 11 with Enterprise Mode and the original Internet Explorer 8. Try it with your own apps, and see for yourself.
Enterprise Mode for Internet Explorer 11 may not fix all compatibility problems, but does work for many of the most common issues. Most importantly, this is an area of continued investment for Microsoft and is a significant step towards helping customers stay up-to-date with the latest version of Internet Explorer.
How is Enterprise Mode managed?

Enterprise Mode for Internet Explorer 11 is turned off by default. When configured with a list of legacy Web apps, IE11 will switch in and out of Enterprise Mode dynamically as users surf the Web. Internet Explorer provides a seamless browsing experience, so users don’t have to worry about which browser to use for which sites.
Corporate IT controls which sites and paths are rendered in Enterprise Mode via a centrally-managed XML list or group of lists. For example, can be set to use Enterprise Mode, while may be set to use modern “Edge” standards mode. A new Enterprise Mode Site List Manager tool is available for managing lists, as shown below.

Enterprise Mode Site List Manager, showing CRM and ERP systems with new (Default) and legacy (Enterprise) paths.
Two registry keys, which can be set via new Group Policies, enable/disable Enterprise Mode and provide a local link or URL path to the XML list. Different divisions or locations, for example, can be configured to use different lists.
Registry Key Function
[HKEY_LOCAL_MACHINE\SOFTWARE\ Policies\Microsoft\Internet Explorer\Main\EnterpriseMode] “Enable” = “” | {URL:port} This setting lets you decide whether users can turn on Enterprise Mode for Web sites with compatibility issues. Optionally, this policy also lets you specify where to get reports (through POST messages) whenever a user turns on or off Enterprise Mode.
[HKEY_LOCAL_MACHINE\SOFTWARE\ Policies\Microsoft\Internet Explorer\Main\EnterpriseMode]
“SiteList” = {File or URL}
This setting lets you specify where to find the list of Web sites you want opened using Enterprise Mode. This list can be maintained using the new Enterprise Mode Site List Manager tool.

Registry keys for enabling Enterprise Mode and pointing to the managed site list.
When enabled, a tool menu option enables end-users to force a page into Enterprise Mode. This can be made available to all users, or select users for testing purposes. This same registry key can be used to collect manual overrides. By configuring the “Enable” key with a valid URL and port, Internet Explorer will initiate a simple POST to the supplied address whenever a user enables or disables Enterprise Mode. This effectively helps customers crowd-source lists of compatible Web apps from their own users, which may decrease triage and testing costs.
To learn more about Enterprise Mode

To learn more about Enterprise Mode for Internet Explorer 11, visit the Internet Explorer TechNet site and view the Build session, Better App Compat with Enterprise Mode for Internet Explorer 11.
Internet Explorer 11 provides increased performance, improved security, and support for the modern technologies like HTML5 and CSS3 that power today’s Web sites and services. By adding better backward compatibility with Enterprise Mode, Internet Explorer 11 now helps customers stay up to date with the latest browser—and facilitates using the latest software, services, and devices.
— Kevin Miller, Program Manager Lead, Internet Explorer
— Fred Pullen, Product Marketing Manager, Internet Explorer