Microsoft Edge Legacy
Microsoft Edge Legacy, originally released as simply Microsoft Edge is a discontinued proprietary cross-platform web browser created by Microsoft. Released in 2015 along with both Windows 10 and Windows 10 Mobile, it was built with Microsoft's own proprietary browser engine, EdgeHTML, and their Chakra JavaScript engine. It was not released for Windows 8.1, Windows Server 2012 R2, and versions released before them.
Microsoft Edge Legacy on desktop was superseded by "The New Microsoft Edge", also known as simply "New Edge", on January 15, 2020. On Xbox consoles, it was superseded in September 23, 2021.
The end of Edge Legacy support on Windows 10 Mobile coincided with the end of support for that platform, on January 14, 2020, while support on desktop ended on March 9, 2021, ending a 14 month support transition grace period. Xbox System Software support ended on September 23, 2021, when it was replaced by New Edge.
Features
Microsoft Edge was the default web browser, replacing Internet Explorer 11 and Internet Explorer Mobile. As its development and release is dependent on the model of Windows as a service, it is not included in Windows 10 Long-Term Servicing Branch/Channel builds.Microsoft initially announced that Edge would support the legacy MSHTML browser engine for backward compatibility, but later said that, due to "strong feedback", Edge would use a new engine, while Internet Explorer would continue to provide the legacy engine. The developer toolset features an option to emulate the rendering behavior of Internet Explorer versions 5 to 11.
Favorites, reading list, browsing history and downloads are viewed at the Hub, a sidebar providing functionality similar to Internet Explorer's Downloads manager and Favorites Center.
Edge features a built-in PDF reader, and supports WebAssembly. Until January 2021, Edge also featured an integrated Adobe Flash Player.
Edge does not support legacy technologies such as ActiveX and Browser Helper Objects; instead, it uses an extension system based on the cross-browser WebExtension API.
Edge integrates with Microsoft's online platforms to provide voice control, search functionality, and dynamic information related to searches within the address bar. Users can make annotations to web pages that can be stored to and shared with OneDrive, and can save HTML and MHTML pages to their computers. It also integrates with the "Reading List" function and provides a "Reading Mode" that strips unnecessary formatting from pages to improve their legibility.
When preliminary support for browser extensions was added in March 2016 with build 14291, only three extensions were initially supported. Microsoft indicated that the delay in allowing extensions and the small number was due to security concerns.
Release cycle
Microsoft Edge Legacy release cadence was tied to the Windows release cycle and used the Windows Insider Program to preview new versions of the browser. These pre-release builds were known as "Edge Preview". Every major new release of Windows 10/10 Mobile included an updated version of Edge Legacy and its render engine until the release of New Edge.Development
In December 2014, writing for ZDNet, technology writer Mary Jo Foley reported that Microsoft was developing a new web browser codenamed "Spartan". She said that "Spartan" would be treated as a new product separate from Internet Explorer, with Internet Explorer 11 retained alongside it for compatibility.In early January 2015, The Verge obtained further details surrounding "Spartan" from sources close to Microsoft, including reports that it would replace Internet Explorer on both the desktop and mobile versions of Windows. Microsoft officially unveiled "Spartan" during a Windows-focused keynote on January 21, 2015. It was described as a separate product from Internet Explorer, although its final name was not announced.
"Spartan" was first made publicly available as the default browser of Windows 10 Technical Preview build 10049, released on March 30, 2015. The new engine used by "Spartan" was available in Windows 10 builds as part of Internet Explorer 11, Microsoft later announced that Internet Explorer would be deprecated on Windows and would not use the "Spartan" engine.
On April 29, 2015, during the Build Conference keynote, it was announced that "Spartan" would officially be known as Microsoft Edge. The browser's logo and branding were designed to maintain continuity with the branding of Internet Explorer. The Project "Spartan" branding was used in versions released after Build 2015. On June 25, 2015, Microsoft released version 19.10149 for Windows 10 Mobile which included the new brand. Version 20.10158 followed on June 28, 2015, for the desktop versions, also including the updated branding. Then on July 15, 2015, Microsoft released version 20.10240 as the final release to Insiders. The same version was rolled out to consumers on July 29, 2015.
On August 12, 2015, Microsoft started the preview program for the next version of Microsoft Edge when they released version 20.10512 to Mobile users. Six days later, version 20.10525 followed for desktop users. These preview versions received multiple updates. On November 5, 2015, Microsoft released version 25.10586 as the final release for Edge's second public release for desktop users. The update was then rolled out to desktop and Xbox users on November 12, 2015. Then on November 18, 2015, the update was rolled out to Windows 10 Mobile, also as the initial release on that platform. Finally, on November 19, 2015, the update was also made available as part of the Windows Server 2016 Technical Preview 4.
In April 2018, Edge added tab audio muting. In June 2018, support for the Web Authentication specifications were added to Windows Insider builds, with support for Windows Hello and external security tokens.
August 2019 saw the removal of Edge support for the EPUB file format.
Microsoft stopped supporting Edge Legacy on March 9, 2021. On April 13, 2021, Microsoft released a cumulative monthly security update which completely removed Edge Legacy and replaced it with the new Chromium-based Edge, if not already present. While the initial release of New Edge on Xbox, as bundled with the September 2021 update, replaced Edge Legacy and marked the end of Xbox System Software support for it.
EdgeHTML
EdgeHTML is the proprietary browser engine developed for Edge . It is a fork of MSHTML with all legacy code of older versions of Internet Explorer removed, with the majority of its source code rewritten to support web standards and interoperability with other modern browsers. EdgeHTML is written in C++.The rendering engine was first released as an experimental option in Internet Explorer 11 as part of the Windows 10 Preview 9926 build.
EdgeHTML is meant to be fully compatible with the WebKit layout engine used by Safari and other browsers. Microsoft stated their original acceptance criteria: "Any Edge–WebKit differences are bugs that we're interested in fixing."
A review of the engine in the beta Windows 10 build by AnandTech found substantial benchmark improvements over MSHTML, particularly its new Chakra JavaScript engine performance, which had come up to par with that of Google Chrome. Other benchmarks focusing on the performance of the WebGL API found EdgeHTML to perform much better than Google Chrome and Mozilla Firefox.
Edge Legacy release history
| Version | Browser engine | Release date | Highlights |
| 20.10240 | EdgeHTML 12.10240 | July 15, 2015 | First public release, initial release for PC
|
| 25.10586 | EdgeHTML 13.10586 | November 5, 2015 | Initial release on Windows 10 Mobile and Xbox System Software |
| 38.14393 | EdgeHTML 14.14393 | August 2, 2016 | Initial release on Windows Holographic |
| 40.15063 | EdgeHTML 15.15063 | April 11, 2017 | |
| 40.15254.603 | EdgeHTML 15.15254 | January 14, 2020 | Final release on Windows 10 Mobile |
| 41.16299 | EdgeHTML 16.16299 | September 26, 2017 | |
| 42.17134 | EdgeHTML 17.17134 | April 30, 2018 | |
| 44.17763 | EdgeHTML 18.17763 | November 13, 2018 | |
| 44.18362 | EdgeHTML 18.18362 | May 21, 2019 | |
| 44.18363 | EdgeHTML 18.18363 | November 12, 2019 | |
| 44.19041 | EdgeHTML 18.19041 | May 27, 2020 |