Attachment wouldn't upload with first message...here's screenshot:

We can not see your system details. So this is only a guess. There is a way that browsers tell websites what their system and browser type is. It might be the information was altered.

Type about:support in the address bar and press enter. Look for; User Agent Copy that line and copy it here.

or

Type about:support in the address bar and press Enter. Under the main banner, press the button; Copy Text To Clipboard.. Then in the reply box at the bottom of this page, do a right click in the box and select Paste. This will show us your system details. No Personal Information Is Collected.

The Update Notice is about Thunderbird not Firefox. If you use Thunderbird go to it and update from there not from this notice.

Damn......

alan_r....thank you! What a fool I am! Sorry for the mistake - must take more care ;) I'll see if I can disable such notices for Thunderbird, then.

FredMcD - thanks for the help, I think alan_r has pointed out the deliberate mistake!

cheers

Hi Hj - I'm happy to have helped. Don't be too hard on yourself. We've all done it. Welcome to the Club.

hj said

I keep getting a seriously irritating popup, even when I'm not running Firefox, saying an update to 45.4.0 is available. Seeing as I am running 48.0.2 this is utterly stupid! What's going on and how do I get rid of this irritating notification? HJ

Note Firefox 49.0 and later Release requires Mac OSX 10.9 and later now. So in order to get security updates with Firefox you need to use the Firefox 45 ESR. The current Release is Firefox 45.4.0esr as it came out when Firefox 49.0 did.

See https://support.mozilla.org/en-US/kb/firefox-osx