14 DAY TRIAL // Mozilla is notifying add-on developers to plan ahead for Firefox 25. It looks like the group wants to push the Australis theme revamp along with Firefox 25, which is currently in the Nightly channel – or, at the very least, it's contemplating it.
Australis still has a lot of rough edges at this point, but Firefox 25 isn't due for the stable channel until October, so there's plenty of time left to get things right.
While there are plenty of changes for users in the Australis UI, there are some for add-on and extension developers as well.
The add-on bar, which is displayed at the bottom and is itself somewhat of a legacy feature, may be removed altogether.
Few people use it now and it clutters up the screen. No decision has been made on whether to remove it altogether, but add-on developers would be wise to assume that it will be gone and design their add-ons around that.
Australis also comes with some changes to the main toolbar. Add-ons will only be able to add a button there, similar to how it works in Chrome, and user-created custom toolbars will likely be removed as well.
Many – if not most – Firefox add-ons already adhere to this style, but not all do. Those that don't may stop working once Australis is enabled by default, unless the developers start reworking them now.
Another major change planned for Firefox 25 as far as add-on developers are concerned is a revamp of the system restore feature. Users won't notice anything, but changes under the hood mean that some add-ons will have to be modified to work with the new code.
Some good news for add-on developers at least is that Firefox 24 is an extended support release, which means big changes are pushed to Firefox 25, which should give them six more weeks to work with.