Firefox 56 add-on compatibility changes break CopperCu add-on

[mike-scott]

When upgrading to Firefox 56, the CopperCu add-on stops working. See Firefox 56 add-on compatibility changes: https://blog.mozilla.org/addons/2017/07/18/compatibility-firefox-56/

[nullr0ute]

With Firefox 57 (Due Nov 14th) this will need to be a WebExtension
https://blog.mozilla.org/addons/2017/02/16/the-road-to-firefox-57-compatibility-milestones/
https://developer.mozilla.org/en-US/Add-ons/WebExtensions

[mkovatsc]

WebExtension do not allow for custom protocol handlers. In some sense, Mozilla killed Copper.
There could be an ugly way where another program is encapsulated to do the UDP/CoAP messaging and have a cryptic URI in the address bar (a bit like the Copper4Chrome Extension). At the moment, I am not motivated to go down this path, though.

Also see https://bug1234567.bugzilla.mozilla.org/show_bug.cgi?id=1271553

[rogierc]

One escape for Copper users would be getting Firefox 52 ESR.
See: https://www.mozilla.org/en-US/firefox/organizations/all/#legacy
This Extended Support Release will still get security updates for quite a while.

I am using this firefox ESR version for now, because Copper is too valuable when developing CoAP applications. Hope there is going to be a durable solution in time.

[mcr]

The mozilla ESR page now offers Firefox 60, alas. Maybe the older one is available somewhere I couldn't see.

% sudo apt-get install firefox-esr
on a machine with access to Debian Stale (oldstable) gets me firefox 52. Don't use it as your main browser... and it co-exists with a /usr/local installed firefox from mozilla.org.

Not the best solution, but it still works.