Hi

It is only possible to install the current version available from the App store.

What are the problems that you are seeing? We might be able to help.

The latest version is removing spaces between words as I type commentaries and I have to go back and re-insert spaces ! A real downer. I have reported the problem and only got confirmation that others are also having the problem!!! No suggestions or solutions in days ! Not having the same problem with other browsers ! May have to abandon Firefox....

There are ways of finding the downgrade version of the ipa and installing it via iTunes, but it would depend on the iOS you currently have, and iTunes version. You would have to downgrade iTunes, then download the downgraded Firefox ipa file, then installing it through iTunes, hoping there aren't any compatibility issues with the updated iOS and the downgraded ipa file.