Are you using normal Firefox? esr, developer . . .

Are you currently using a version from the repositories of your Linux distribution? Try the Firefox version from the official Mozilla server: https://www.mozilla.org/en-US/firefox/all/

My current FF version is 88.0 [64 bit]. Websites are flagging FF 88.0 as outdated. There is a 88.01 version shown as available. Latest available FF version is 93.0 Firefox Releases Updating using the Help > About function does not show any available updates. Can someone please explain what is going on? Thanks.

In your More System Details on right User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:88.0) Gecko/20100101 Firefox/88.0

The minor versions is not shown in UA ever since the Fx 16.0.1 Release so even if you had Fx 88.0.1 it will still show as 88.0

You appear to be using a package build from Ubuntu so your Firefox updates will be from them in your package manager, that is if Ubuntu is still supporting Firefox updates on the old ubuntu 16.04 LTS that was released way back on Apr 21, 2016 according to Distrowatch besides the security updates for a while still as 16.04 LTS is considered EOL.

Only the official builds of Firefox (for Linux) from mozilla.org get internal updates from Mozilla as Mozilla does not provide updates to builds they did not well build. This is why there is no updates in your ubuntu build of Firefox.

If you do use Firefox from www.mozilla.org/firefox/all/ I suggest make sure the Firefox folder has read/write permissions for the user so you can get updates. If you are the only user then a easy way is to have Firefox in its own folder in HOME.

• userAgent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:88.0) Gecko/20100101 Firefox/88.0
• osVersion: Linux 4.15.0-142-generic #146~16.04.1-Ubuntu SMP Tue Apr 13 09:27:15 UTC 2021
• distributionID: canonical

You are using an old Ubuntu 16.04.1 version that is no longer supported. Another similar recent thread:

• /questions/1353873 Why was firefox 88.0 not updated automatically?

cor-el

You are correct, I did not realize 16.04 OS was past regular support - my mistake. For whatever reason, my Google Chrome browser continues to receive updates thru Ubuntu - just had one a few days ago.

Did some more research and discovered that Ubuntu offers Extended Security Maintenance for 16.04, free for personal use.

Ubuntu Advantage for Infrastructure

I am installing now.

cor-el

You are correct. I did find a work around:

Ubuntu Advantage for Infrastructure

Free for personal use.

You're welcome btw.