It sounds like you’re currently on the ESR (Extended Support Release) version of Firefox. Firefox 140.9 is the latest update for the ESR branch, which is why your browser says it is "up-to-date".

Is this a personal computer or a work/school-managed device?

Windows 10 or 11 or?

If they answer that it's a personal computer and you have Windows 10 or 11, you can go to firefox.com and download the latest release.

Hi, thanks for your reply. I am using a Mac PC. iMac with M3 chip running latest Tahoe OS. Firefox says it is running ESR. I always instal the latest Firefox updates as soon as they become available and it does say 'Up to date' so unclear why it is not running the latest 149?

Don't need to be on ESR.

Maybe you might have accidentally clicked the "Extended Support Release" link on the download page at some point.

Download the Standard Version from Official site Download Firefox for macOS

Don't forget to keep backup your Bookmarks, History etc.. or just use Sync for that.

OK, will look into my options - many thanks for your help.