I have created a toolbar button. It is working fine on my laptop running FF 48. However, I am unable to add it to the toolbar in my friend’s system running FF 45.7.0. Nothing happens when I click Load Temporary Add-on button on the about:debugging page.
I have followed the procedure given here.
Is this the compatibility issue? Or something else?
Do you really want/need to support Firefox 45 with your WebExtension?
FF45 only has very basic support for some of the APIs, there is a lot still missing.
And FF45 won’t even be ESR for much longer.
Unless it’s some kind of cooperative laptop, just tell him to update his browser.