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The trouble is that most enterprise deployments of Windows haven’t taken advantage of the speed
and standards compliance of the latest Internet Explorer release but are instead stuck on an old version,
one that’s slow and increasingly unable to keep up with the modern web. The reason is most often
compatibility with legacy web apps that typically require Internet Explorer 8 to work properly.
The problem is exacerbated by the fast-paced development cycles of competing browsers, including
Google Chrome and Mozilla Firefox, which in recent years have pushed out automatic updates for
their Windows browsers far more frequently than Internet Explorer.
In general, that fast update cycle means anyone using Chrome or Firefox has quicker access to
features based on the latest web standards. Meanwhile, Microsoft’s overly generous support life cycle
has allowed older versions of Internet Explorer to remain in use years longer than is sensible on the
fast-changing modern web.
As of January 12, 2016, that all came to an end. On that date, Microsoft changed its support life cycle
for Internet Explorer. Under the new policy, only the most recent version of Internet Explorer available
for a supported operating system will receive technical support and security updates.
For the first time, only one version of Internet Explorer, Internet Explorer 11, is officially supported
on PCs running Windows 7, Windows 8.1, and Windows 10. A feature called Enterprise Mode for Internet
Explorer 11, which I discuss later in this chapter, is designed to address compatibility issues in the enterprise.
But Internet Explorer isn’t the default web browser for new PCs running Windows 10. That honor goes
to the new Microsoft Edge. Enterprises can still choose to make Internet Explorer their default browser
across all supported Windows versions, but otherwise Internet Explorer will be relegated to a compatibility
role.
In the next section, I explain the similarities and differences between the two Windows 10 browsers.
Browsing options in Windows 10
The two-browser strategy for Windows 10 isn’t a new idea. Windows 8 and Windows 8.1 also included
two browsers, one with the conventional Windows desktop interface and the other with a modern,
touch-friendly design intended for full-screen use on tablets. Despite the different designs, the two
browsers shared a great deal of common code, most notably the Trident rendering engine, which has
been at the core of Internet Explorer since its earliest days.
Windows 10 also includes two browsers, each with a different design and different methods of user
interaction. More importantly, though, Windows 10 includes two different rendering engines:
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EdgeHTML (Edgehtml.dll) is the new HTML viewer. Although its starting point was the
original Trident engine, it has since diverged from that engine significantly. The new engine
deliberately eliminates large chunks of legacy code designed to emulate older Internet Explorer
versions, including the versioned document modes that determine how previous versions of
Internet Explorer render a page. Although compatibility with standards is an important goal of
78 CHAPTER 6 Microsoft Edge and Internet Explorer 11