Phil

If there is poor communication it might be that authors want to wait for release “just to be sure” there won’t be any more changes that affect their extension. It might be possible to make a better effort at letting people know new RCs won’t break them.

About add-on updating, the older, more popular and most used ones are (just about) always kept up to date so that shouldn’t be the reason for mass amounts of users not upgrading Fx despite what some sample feedback might say. For the add-ons that aren’t updated that people hold out on and that don’t upgrade Fx because of, those are mostly flash in the pan ones that are the biggest issue. The ones where a developer’s add-on becomes massively popular and they decide not to update it and maintain it for whatever reason (usually because of time constraints and real world issues). There’s a long list of those but more often than not, new developers will take on, or adapt that add-on but not in time for the latest product release.
A few solutions for that would be;
Developer’s who have no plans on maintaining their add-on(s) for the next Fx (or other) release should have their add-on(s) dropped from the recommended add-ons list.
Those developers should make clear that they’ll no longer be maintaining their add-on and encourage, and work with those that might be interested in taking over. A simple notice in the add-on’s description on AMO isn’t good enough. Other developers don’t see it.
Creating a new category in the AMO (and perhaps mozillaZine) forums plus adding AMO and Mozilla site promos to “Adopt an Add-on” wouldn’t be a bad idea at all.
When an add-on becomes incompatible with the most recent version of a Moz product, it should be moved to a new “Incompatible” Add-ons category where users have to implicitly choose to view them like they have to for experimental ones and not be made available through AMO’s general search. There are still add-ons that show up for Fx 1.
Providing some sort of extra recognition and perhaps an AMO award or badge for add-ons that are successfully upgraded to be compatible with the next Moz product release is a good idea also, and of course recognize the developers too. It amazes me how many developers there are that have consistently maintained their add-ons since the initial release (or soon after) of Firefox. Ed Hume, Mel Reyes, and Aaron to name a tiny few. They should get extra exposure and recognition and an award/badge type system would show end users that they can count on their add-on being available and compatible in the future.
As far as I’m aware, there isn’t any means of communicating directly with individual developers to both remind them to prepare their add-on for the next product release, and find out if they’ll be bothering to update it all. There’s a few blogs and newsgroups, but there should be a newsletter and survey that goes directly to developers. If they don’t plan on maintaining their add-on(s), then they should be encouraged to add it to the Adopt an Add-on thread (or have it added on behalf of them, I’ll volunteer to do it). The Add-on Compatibility Reporter is a great step but not a comprehensive solution.

@James: yes, we send an email to our top add-on authors (based on usage) in order to warn them about the upcoming release. Sending a message to *all* authors may be a little overkill, considering that many are not active or interested in updating. Many opt out of compatibility notifications as well.

Why not mail them when the beta is out (or whenever the api is stable) and ask them to update their extensions to be compatible? (Or has that been tried already?)

Should be interesting to see the first one hundred downloaded extension update responsiveness.