How can I check what version # of Firefox that I have/ I have upgraded today but do not know what version I have?

Click the menu button at the right side of the Firefox toolbar, go to Help, and select About Firefox. The About Mozilla Firefox window with the version number will open.

Note this is a thread on a community support forum and is not some form of direct chat system. Replies can take from minutes to hours or longer.

From one of your two duplicate threads /questions/1557714 this is about a bank site?.

I know banks like Chase and Citi fairly recently made it so you need Firefox 128.0 or later.

You appear to be using Windows 7 so the most current Firefox version you can run is Firefox 115 ESR currently at 115.31.0esr. https://support.mozilla.org/en-US/kb/firefox-users-windows-7-8-and-81-moving-extended-support

To be able to run Firefox 116.0 and later including the current Firefox 140.6.0esr and 146.0.1 Release requires Windows 10, 11. The other option is more technical as in dual booting with a current Linux distro in order to use current Firefox versions whether as a tarball from Mozilla or by snap, flatpak, deb, rpm.

There is something you can try to fool the bank sites into thinking you have a more current version.

1. In a new tab, type or paste about:config with a colon : in the Location (address) bar and press Enter/Return. Click the button accepting the risk.
2. In the search box on top of the page, type or paste forceVersion and pause while the list is filtered
3. Double-click the network.http.useragent.forceVersion preference to display an editing field, and change the value to 128 or 140 then press Enter/Return or click the blue check mark button to save the change.