Internet Explorer 1 - 5 Versions

Internet Explorer 1

The first version of Internet Explorer (later referred to as Internet Explorer 1) made its debut on August 16, 1995. It was a reworked version of Spyglass Mosaic, which Microsoft had licensed, like many other companies initiating browser development, from Spyglass Inc. 

It came with Microsoft Plus! for Windows 95 and the OEM release of Windows 95, and was installed as part of the Internet Jumpstart Kit in Plus!.[ The Internet Explorer team began with about six people in early development. 

Internet Explorer 1.5 was released several months later for Windows NT and added support for basic table rendering. By including it free of charge on their OS, they did not have to pay royalties to Spyglass Inc., resulting in a lawsuit and a multi-million USD settlement.

Internet Explorer 2

Internet Explorer 2 was released for Windows 95, Windows NT 3.5, and NT 4.0 on November 22, 1995 . It featured support for SSL, cookies, VRML, RSA, and Internet newsgroups. Version 2 was also the first release for Windows 3.1 and Macintosh System 7.0.1 , although the Mac version was not released until January 1996 for PPC, and April for 68k. 

Version 2.1 for the Mac came out in August 1996, although by this time, Windows was getting 3.0. Version 2 was included in Windows 95 OSR 1 and Microsoft's Internet Starter Kit for Windows 95 in early 1996. 

It launched with twelve languages, including English, but by April 1996, this expanded to 24, 20, and 9 for Win 95, Win 3.1, and Mac, respectively. The 2.0i version supported double-byte character-set. 

Internet Explorer 3

Internet Explorer 3 was released on August 13, 1996, and went on to be much more popular than its predecessors. Internet Explorer 3 was the first major browser with CSS support, although this support was only partial. 

It also introduced support for ActiveX controls, Java applets, inline multimedia, and the PICS system for content metadata. Version 3 also came bundled with Internet Mail and News, NetMeeting, and an early version of the Windows Address Book, and was itself included with Windows 95 OSR 2. 

Version 3 proved to be the first more popular version of Internet Explorer, bringing with it increased scrutiny. In the months following its release, a number of security and privacy vulnerabilities were found by researchers and hackers. This version of Internet Explorer was the first to have the 'blue e' logo. The Internet Explorer team consisted of roughly 100 people during the development of three months. 

The first major IE security hole, the Princeton Word Macro Virus Loophole, was discovered on August 22, 1996 in IE3. Backwards compatibility was handled by allowing users who upgraded to IE3 to still use the last IE, because the installation converted the previous version to a separate directory. 

Internet Explorer 4
Internet Explorer 4, released in September 1997, deepened the level of integration between the web browser and the underlying operating system. Installing version 4 on a Windows 95 or Windows NT 4 machine and choosing Windows Desktop Update would result in the traditional Windows Explorer being replaced by a version more akin to a web browser interface, as well as the Windows desktop itself being web-enabled via Active Desktop. 

The integration with Windows, however, was subject to numerous packaging criticisms (see United States v. Microsoft). This option was no longer available with the installers for later versions of Internet Explorer, but was not removed from the system if already installed. Internet Explorer 4 introduced support for Group Policy, allowing companies to configure and lock down many aspects of the browser's configuration as well as support for offline browsing. 

Internet Mail and News was replaced with Outlook Express, and Microsoft Chat and an improved NetMeeting were also included. This version was also included with Windows 98. New features that allowed users to save and retrieve posts in comment forms were added, but they are not used today. Internet Explorer 4.5 offered new features such as easier 128-bit encryption. It also offered a dramatic stability improvement over prior versions, particularly the 68k version, which was especially prone to freezing.

Internet Explorer 5

Internet Explorer 5, launched on March 18, 1999, and subsequently included with Windows 98 Second Edition and bundled with Office 2000, was another significant release that supported bi-directional text, ruby characters, XML, XSLT, and the ability to save web pages in MHTML format. IE5 was bundled with Outlook Express 5. 

Also, with the release of Internet Explorer 5.0, Microsoft released the first version of XMLHttpRequest, giving birth to Ajax . It was the last with a 16-bit version. Internet Explorer 5.01, a bug fix version included in Windows 2000, was released in December 1999. 

Internet Explorer 5.5 followed in July 2000, improving its print preview capabilities, CSS and HTML standards support, and developer APIs; this version was bundled with Windows Me. 

However, version 5 was the last version for Mac and UNIX. Version 5.5 was the last to have Compatibility Mode, which allowed Internet Explorer 4 to be run side by side with the 5.x. The IE team consisted of over 1,000 people by 1999, with funding on the order of US$100 million per year.