Firefox 26 will be released on December 10th. Here’s the list of changes that went into this version that can affect add-on compatibility. There is more information available in Firefox 26 for Developers, so you should read that too.
- Pass _firstTabs ‘parameter’ as an argument to restoreWindow() rather than tacking it onto the state object.
_firstTabsno longer serves any purpose, and the
restoreWindow()function should be used instead.
- Merge the Tabs category into the General category in in-content preferences. This bug made me realize that about:preferences is a thing. It’s still under construction, as this bug makes it clear.
- Deprecate OS.File.Info.prototype.creationDate.
- Remove Components.lookupMethod. This function is no longer necessary to use.
- Don’t call into nsIAccessibleProviders. nsIAccessibleProvider was removed, so you should not reference it from your XBL bindings anymore.
- Remove nsIHistoryEntry and replace it with nsISHEntry.
- Remove memory uni-reporters. This changes the interfaces and implementations around nsIMemoryReporter.
- Tabs are duplicated after going back to Firefox for Android. This changes nsISessionStore on Firefox for Android.
- Refactor nsStrictTransportSecurityService. nsIStrictTransportSecurityService is now nsISiteSecurityService.
- Mark nsIContentPrefService as deprecated in favor of nsIContentPrefService2.
- Binary compatibility broken for maintenance releases due to strict version-script. This is actually a fix that improves compatibility for binary add-ons. A recent change made it more difficult for binary add-ons to stay compatible because they needed to be rebuilt for minor version updates.
- Make nsGenericHTMLElement implement nsIDOMHTMLElement. This is an internal refactoring that only affects binary add-ons.
- document.getAnonymous* should not be available to web content. Whitelisted remote XUL should continue to work.
- Hide XULElement from content.
- Add deprecation warnings for mozGetAsFile. This canvas function is now deprecated, in favor of
- Remove support for chrome access to history[n]. This removes a few chrome-only, Firefox-only properties of the
history.previouswere also dropped.
- nsIAppStartup should be able to tell whether the app was restarted.
- Create a JS add-on API for adding content to the promotional banner. This API allows add-ons to easily show content in the default home page. The API is documented here.
Please let me know in the comments if there’s anything missing or incorrect on these lists. If your add-on breaks on Firefox 26, I’d like to know.
The automatic compatibility validation and upgrade for add-ons on AMO will happen very soon, so keep an eye on your email if you have an add-on listed on our site with its compatibility set to Firefox 25.