custom mode not work

helpful and informative

I had an addong called useragent switcher before and this aint it! Wish I could find it. I don't know what to do in this current version. I used the button on the tool menu and selected a newer version of Firefox but when I click test it still shows my actual version--52.5 ESR and it doesn't fool the addons site when I try to install a new addon. So far none of the user agent addons are working, so adding to the list of fails.

Can you spoof UserAgent from header ?
Check on https://browserspy.dk/useragent.php
Not working on first visit.

There was an issue on Linux several months back that seemed to ignore some of the agent settings, but this appears to have been fixed. Thank you! Recommended, great extension.