I hope that this is the right forum for this question!
Mozilla has announced that support for all extension technologies other than WebExtensions will cease when Firefox 57 is launched; this is scheduled for November this year. At this point, most existing add-ons will cease to function, and many (or most?) authors will not be re-writing them as WebExtensions.
I have been unable to find any reference to the implications for CID users? Will CID change in the same way?