Internet Explorer 4

Internet Explorer 4 is a version of Internet Explorer, released in September 1997 for Windows and 6 January 1998 for Mac OS. It can run on Windows 3.1, 95, 98, NT 3.51, NT 4.0, Mac OS 7.1+, and Solaris. Installing Internet Explorer 4 on Windows 95 or Windows NT 4.0 gave users an option to enable the 'Windows Desktop Update', which adds Internet Explorer integration to various parts of the OS. This includes replacing the traditional Windows Explorer with a web browser-like interface, and Internet-enabling the desktop itself via Active Desktop (which includes the infamous 'channel bar' of advertising links). Internet Explorer 4 shipped with Windows 95 OSR 2.5, Windows NT 4.0 Terminal Server Edition (4.01, albeit being an optional install and without Windows Desktop Update) and Windows 98 (4.01 SP1) and was later released for Macintosh.

This version also updates parts of the logo branding, so that Internet Explorer now fully uses the well-known "e" icon introduced in Internet Explorer 3.

Version 4.5
Internet Explorer 4.5 is a version of Internet Explorer 4 for Mac OS, which was released on 5 January 1999. This version drops support for 68k processors.

CD releases
Internet Explorer 4 was available as a download and was also shipped on CDs. The CD release was available in two variants:
 * one, simply known as "Internet Explorer", which included add-ons for Internet Explorer and the browser itself in the x86 (32-bit) and DEC Alpha architectures, and
 * another one known as "Internet Explorer Plus", which also includes the 16-bit edition for Windows 3.1x and NT 3.51 and the Macintosh edition (m68k and PowerPC).

Easter egg
There is a hidden easter egg in this version. To activate the egg, open the About dialog box, drag the IE logo to the globe while holding the ⇧ Shift key, then push the "Microsoft Internet Explorer 4.0" wordmark away. A "Unlock" button appears; click on it and drag the logo to the globe. The globe will zoom up and a list of Internet Explorer developers will show up.