This is the final test build of IE11 for Windows 7 before general availability of this version of the browser. IE11 for Windows 7 is due out some time "later this fall." Microsoft officials aren't providing a specific date. IE11 for Windows 8.1 will be generally available on October 18, the day that Windows 8.1 launches.
IE11 for Windows 7 includes many, but not all, of the same features that are in the Windows 8.1 version.
Here's what's different:
In the Windows 7 version of IE11, the URL bar remains at the top of the browser (like it is with IE10 on Windows 7). IE11 for Windows 8.1 puts the URL bar at the bottom.
Since Windows 7 does not offer the “metro”/modern UI like Windows 8 and 8.1, some of the enhancements specific to that UI don’t carry over, such as the new tab view. (However, while being able to open 100 tabs simultaneously in the modern mode is new, it’s been possible to view unlimited tabs in the desktop version for a while.)
IE11 on Windows 7 won't support for premium video extensions like the 8.1 version does. "There are many solutions available for Windows 7 customers to stream and view protected content online, those methods will continue to function for customers," a spokesperson confirmed. (Read: Silverlight and Flash.)
No support for Google's SPDY protocol (the precursor to HTTP 2.0) in IE11 on Windows 7. IE11 on Windows 8.1 does support SPDY.
IE11 on Windows 7 will not support Enhanced Protected Mode browser security enhancements. (IE10 on Windows 7 didn't, either.)
The UI Responsiveness tab is disabled in the F12 developer tools. However, support for this will be coming by the time the final version of IE11 for Windows 7 is released, thanks to "an update to the underlying Windows 7 platform."
Beyond this handful of differences, IE11 for Windows 7 and IE 11 for Windows 8.1 are largely the same, according to Microsoft officials.
The updated release preview includes a number of performance enhancements that Microsoft has made since the developer preview was released. It also includes a few new features of interest specifically to developers.
According to a posting on the IE Blog, now that the Pointer Events specification is a Candidate Recommendation at the W3C, IE11 supports an un-prefixed version of the emerging standard. "With Pointer Events support across the full range of Windows devices (and soon to other browsers), web sites can easily build experiences that work equally well with mouse, keyboard, pen, and touch," officials said.