Φόρουμ υποστήριξης - Firefox

How do I turn off those annoying "update available" notifications/reminders that keep popping up? I've gone into Settings, and in the Updates section firefox only let's me select auto updates or check for updates. I searched online but couldn't seem to find anything about how to disable the notifications all together with the newer version of FF. It's driving me crazy, thinking of switching browsers because of this. Thanks in advance!

When I press the pause button on my keyboard, it doesn't stop the YouTube video like it used to. I'm not sure why it stopped working. I've checked the key, and it works fine in Chrome.

I am trying to add custom search engines to Firefox. I have tried the steps given in the forum thread https://support.mozilla.org/en-US/questions/1212596.

However when I try to go and add the search engine as per the article given above I do not get the option. Please see the attached screen shot for more details. I do not want to add an extension or a plugin, but just manually have the option of adding search engines.