Firefox 36 will be released on February 24th. Here’s the list of changes that went into this version that can affect add-on compatibility. There is more information available in Firefox 36 for Developers, so you should also give it a look.

General

XPCOM

Update: folderReadonly doesn’t pertain to bookmarks or results. This removes setFolderReadonly and getFolderReadonly from nsINavBookmarksService .

folderReadonly doesn’t pertain to bookmarks or results. This removes and from . Port BoxObject to WebIDL . This removes various internal interfaces that extend nsIBoxObject , like nsIPopupBoxObject , nsITreeBoxObject , and nsIEditorBoxObject . If you’re using QueryInterface with these interfaces in your code, you can probably just remove the call.

. This removes various internal interfaces that extend , like , , and . If you’re using with these interfaces in your code, you can probably just remove the call. nsIDOMGlobalObjectConstructor is dead code.

Wrappers

There are a number of wrappers that are applied whenever chrome JS objects interact with content JS objects. They are meant to protect privileged code from malicious or otherwise misbehaving content code. The following bugs removed some features in wrappers that could lead to unexpected problems in your chrome/content code. However, you should keep in mind that Multiprocess Firefox is coming, and that means you should be changing your code anyway (some wrappers are still involved, but they should be rare).

Please let me know in the comments if there’s anything missing or incorrect on these lists. If your add-on breaks on Firefox 36, I’d like to know.

The automatic compatibility validation and upgrade for add-ons on AMO will happen within a week or two, so keep an eye on your email if you have an add-on listed on our site with its compatibility set to Firefox 35.