I have two addons with a decent number of downloads. Both addons are on Status Bar. Now I get a lot of emails that say that status bar is gone, and I need to use addon bar. Doesn't addon bar come automatically if you have addons on status bar?
As a developer, what should I fix?
The status bar is gone since quite some time (Firefox 4, really), but there was a compatibility layer that automatically put status bar items from add-ons into the then new add-on bar and automatically toggled the visibility of the add-on bar when this happened.
The Firefox Australis theme, which shipped with Firefox 29, also removed the add-on bar. Again there is a compatibility layer that would place items from the add-on bar into the default toolbar area, but as compatibility layers go, this cannot work with everything, and really only works with standard toolbar buttons added the standard overlay way.
You'll need to convert your statusbar-based stuff to either toolbar buttons overlays (additional remarks for Australis), use the new CustomizableUI API or convert your add-on into an SDK add-on and use SDK ActionButton APIs.