Since Firefox 67, dedicated profiles are used for each new Firefox version.
What profile changes were made in Firefox 67?
Some users have multiple installations of Firefox, each in separate program folders. These separate Firefox installations previously shared a single profile by default. Starting with Firefox version 67, Firefox uses a dedicated profile for each installation of Firefox (including Nightly, Beta, Developer Edition, and ESR installations). This makes Firefox more stable when switching between installations on the same computer and also allows you to run different Firefox installations at the same time.
Tip: To see what Firefox version you're on, see Find what version of Firefox you are using.
You will not lose any personal data or customizations. Any previous profile data is saved and associated with the first Firefox installation that was opened after this change.
Do you have a backup of your profile? The browsing history, etc. probably isn't gone but just incompatible with the current version of Firefox. I can't test for sure since I don't have such an old profile.
I would recommend incrementally upgrading like JMY1000 mentioned in the comments. If you're starting with Firefox 32 that's a quite while back.
Download the previous versions from here: https://ftp.mozilla.org/pub/firefox/releases/
If this is for Windows, you'll want to go into the version you want -> win32 -> en-US to find the setup .exe's (e.g. https://ftp.mozilla.org/pub/firefox/releases/32.0/win32/en-US/).
I'm not sure how much you can jump between rapid releases but you could follow the sections that are broken down here to be safe: https://en.wikipedia.org/wiki/Firefox_version_history#Rapid_releases. Once you get to 67 you may need to upgrade the version one by one due to the dedicated profiles.