What does Firefox team do to ensure that no change are introduced to the interface used by modules/pluig-ins/extensions ?

Question

Every time there's an update my plug-ins seem to be at risk and some of them are not free, I am running v29 and I will roll back to a previous version and turn off any update/upgrade features, too much waste of time on my side.
I think Firefox team should learn to limit the changes they are doing specially if the interface with other add-ons is concerned. I worked in developement many years, I know it is fun and stimulating to introduce something new but it should never impact negatively the quality of the existing features so it requires discipline and patience, no place for impulsive actions.
When I get an update, I do not expect it to be a beta that impacts existing features.

Answer 1

Add-ons are developed by third-party developers, and as such there is no guarantee they won't break. We aren't responsible for them or for making sure the millions of add-ons in existence all work properly in every version of Firefox (If we were, we might as well give up on Firefox).
That being said, we do try to restrict breaking changes to the code that Add-ons use. Sometimes it is inevitable, but we make sure to give add-on authors plenty of warning (usually 12-18+ weeks) before a change that might break their extension. We also automatically check every extension installed on our site for things that might not work in new versions, and every extension that passes (the vast majority) are default to be compatible with the new version without the add-on author having to do anything.
Unless you have a third-party binary extension. These are commonly Anti-virus toolbars, etc. These extensions stop working with updates frequently. This is because these companies don't bother to read our notes of what's changing or to release updates for their software until after release.