There are many reasons for installing multiple versions of the Firefox browser on your Windows PC. One of the reasons these days is that some people want to use the older Firefox extensions that no longer work in Firefox Quantum (version 57 and above) – they can use Firefox version 56 or below. Another reason is that you do not use too many of your system resources (very old versions of Firefox use very less memory). And if you are a web developer, then you may want to see how your latest web project works in different versions of the Firefox web browser.
No matter what the reason is, you can install multiple versions of Firefox browser in your Windows PC through Utilu Mozilla Firefox Collection. It is a huge package of all the Firefox versions from version 2.0 to the latest version of Firefox. Not only it contains all the final release versions, but it also has ESR versions as well as the latest nightly version. Furthermore, all the browser versions come packed with some extensions useful for developers such as Firebug and Web Developer. Adobe Flash Player plugin also comes pre-installed. The package can be installed on Windows 98 and above even though some Firefox versions do not work in older versions of Windows.
The current version 1.1.9.9 of Utilu Mozilla Firefox Collection is nearly 1.2 GB in size. During the installation, you can choose which versions of Firefox browser you want to install. You can select one, more than one or all of them. The installation is done in such a way that you can run multiple versions simultaneously. However, running so many versions of Firefox at the same time might choke even a powerful computer. It comes with a tool that helps you launch the same URL in all the versions at the click of a button.
Conclusion: Utilu Mozilla Firefox Collection packs all the Firefox versions in a single easy to install setup. With all the useful extensions, it is geared towards the web developers. But if you want just two or three different versions of Firefox, you can manually download them from Mozilla servers yourself.
You can download Utilu Mozilla Firefox Collection from https://utilu.com/UtiluMFC/.