👉
If you specifically need for legacy testing or compatibility with an old system, here’s what you should know:
Here’s a helpful, accurate post regarding – keeping in mind this is a very old, pre-release version from late 2010/early 2011. Title: Looking for Firefox 4.0 Beta 12? Important info before you download.
Firefox 4.0 Beta 12 is over a decade old, contains numerous unpatched security vulnerabilities , and should not be used as your everyday browser for banking, email, or general web browsing.
Mozilla maintains an official archive of old beta releases. You can download Firefox 4.0 Beta 12 here: