Webmasters never know what they are up to when testing websites in various versions of Internet Explorer. It might look fine in Internet Explorer 6 but Internet Explorer 8 might break it. It is therefor of uttermost importance to test a website in different versions of Internet Explorer before releasing an update to the public.
The problem begins when the webmaster realizes that Microsoft has made it virtually impossible to install and use different versions of Internet Explorer on the same computer system. Unlike Firefox or Opera, which allow installations of different versions, that option has been neglected by Microsoft when it comes to Internet Explorer.
A first step in the right direction was the IETester tool which emulated various Internet Explorer versions in one interface making it possible to view websites with different Internet Explorer versions.
Note: Another option is virtualization. This has become even more important in recent years as Microsoft limits Internet Explorer versions and Microsoft Edge in regards to supported operating systems. In short, unless you run the latest version of Windows, you cannot use Microsoft Edge at all, and may not have access to the most recent Internet Explorer versions either.
Internet Explorer Collection
The next step however (compared to IETester) is the Internet Explorer Collection. The collection comes with several Internet Explorer versions from Internet Explorer 1 to Internet Explorer 8 in one installation package. It does include the highly popular Internet Explorer 6, Internet Explorer 7 and 8, and also -- very -- old versions of the browser.
- Internet Explorer 1.0 (4.40.308)
- Internet Explorer 1.5 (0.1.0.10)
- Internet Explorer 2.01 (2.01.046)
- Internet Explorer 3.0 (3.0.1152)
- Internet Explorer 3.01 (3.01.2723)
- Internet Explorer 3.03 (3.03.2925)
- Internet Explorer 4.01 (4.72.3110.0)
- Internet Explorer 5.01 (5.00.3314.2100)
- Internet Explorer 5.5 (5.51.4807.2300)
- Internet Explorer 6.0 (6.00.2800.1106)
- Internet Explorer 6.0 (6.00.2900.2180)
- Internet Explorer 7.0 (7.00.5730.13)
- Internet Explorer 8.0 (8.00.6001.18702)
The best part is that you can pick the Internet Explorer versions that you want from the list of supported ones. You can install them on a supported system separately, so that it becomes possible to test websites and services using different versions of Microsoft Internet Explorer using the same user account.
When you run Internet Explorer Collection after installation, an installation dialog is displayed which you use to select the Internet Explorer versions that you want installed on the system.
It does not make much sense to install the earlier versions, at least when website testing is the main consideration for installing the different versions. It could be nice for a nostalgic trip however or just for fun to see how fast (or not) those old versions were.
Each version of Internet Explorer that has been installed on the system because accessible through the Windows Start Menu. A click on the Internet Explorer icon will launch that version, it is even possible to launch and run several versions of Internet Explorer side by side.
The developer of Internet Explorer Collection is shy on words because there is virtually no information on the website about the technique that is used to run the Internet Explorer versions on the same computer system.
Update: The collection has not been updated in recent time with new versions of Internet Explorer. This means that you are still limited to Internet Explorer 8 and earlier; the program runs on all recent versions of Windows and Windows Server however.