Version 0.9.6.18 was released September 12, 2015

iirc, that extension was abandoned quite awhile ago, hence no updates as of late.

Contact page for that extension developer is here: http://speeddial.uworks.net/contact.html

Well i find it very useful and was working fine up until today. It is listed as an existing extension still so why should it not be fixed just because it hasn't needed any changes since 2015? It is the new update that broke it.

Yes, the latest update may have caused that extension to quit working or not work correctly any longer. With the changes that have been made as each new version has been released since around Firefox 38 (May 2015) or so, many extensions have needed to be updated due to changes made in Firefox. Most extensions that have been "broken" have been fixed by their developer, while others have been abandoned and others have been "adopted" by new or different add-on 'developers' who wanted to keep specific extensions compatible with new versions of Firefox for their own use.

Did you try a different version of "Speed Dial" that was created by a different person? https://addons.mozilla.org/en-US/firefox/addon/fvd-speed-dial/ The user reviews in the last few days (since Firefox 51 was released) of that one indicate that it is probably working in Firefox 51. Unless those users were using an older version of Firefox.

Thanks for the recommendation. I've installed it and imported my dials from the old app but i can't see where you set the numbers e.g. press 1 for dial #1, press 2 for dial #2 etc Any ideas?

ok i spoke with the support of Speed Dial FVD and it doesn't do the same thing. they haven't yet developed "hotkeys" where you type "1" in the browser and it goes direct to Dial#1. they just have a panel of the clickable dials but that functionality wasn't broken in the original Speed Dial, just the "hotkeys"

i emailed the developer of the original Speed Dial a week ago but he's not answering.

it's hard to get out of the habit of typing the speed dials into browser, it just googles the number now. it was such a useful extension. maybe extensions should be removed from the list of available extensions when they are abandoned to avoid disappoinment? any other suggestions ?