I updated manually now. Would still be interest why it claimed to be up-to-date

Your User Agent Shows: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0

Separate Issue; Your System Details shows;

Installed Plug-ins

Shockwave Flash 18.0 r0 Shockwave Flash 21.0 r0
Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer.

Flash: Grab the uninstaller from here: Uninstall Flash Player | Windows Uninstall Flash Player | Mac

Then reinstall the latest version.

Note: Windows users should download the active_x for Internet Explorer. and the plugin for Plugin-based browsers (like Firefox).

Note: Windows 8 and Windows 10 have built-in flash players and Adobe will cause a conflict. Install the plugin only. Not the active_x.

Flash Player Version: 21.0.0.242 Flash Player (Linux) Version 11.2.202.621

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download.

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download.

ropoman said

I updated manually now. Would still be interest why it claimed to be up-to-date

The Win64 Firefox Releases was first listed on www.mozilla.org/firefox/all/ even though the first Win64 Firefox Release was 42.0

In order to get Win64 Firefox 42.0 you had to download from say archive.mozilla.org

Its possible the Firefox 42.0 you had was not the Firefox 42.0 Release if you did not get it from Mozilla.