MDN’s new design is in Beta! A sneak peek:

Add-ons using the techniques described in this document are considered a legacy technology in Firefox. Don't use these techniques to develop new add-ons. Use WebExtensions instead. If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions.

From Firefox 53 onwards, no new legacy add-ons will be accepted on (AMO).

From Firefox 57 onwards, WebExtensions will be the only supported extension type, and Firefox will not load other types.

Even before Firefox 57, changes coming up in the Firefox platform will break many legacy extensions. These changes include multiprocess Firefox (e10s), sandboxing, and multiple content processes. Legacy extensions that are affected by these changes should migrate to WebExtensions if they can. See the "Compatibility Milestones" document for more.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.

UpdateInfo objects hold information about available versions of add-ons and are generated as a result of an update check performed by AddonUpdateChecker.


Attribute Type Description
version string The version of the update.
updateURL string The updateURL that the update can be downloaded from.
updateHash string A hash for the update's file.
updateInfoURL string A URL containing simple release notes for the update.
targetApplications object[] Information about what applications the update is compatible with. Each item in the array contains "id", "minVersion", and "maxVersion" properties.


Document Tags and Contributors

 Contributors to this page: bunnybooboo, Leif-AMO, kscarfone, Sheppy, trevorh, Mossop
 Last updated by: bunnybooboo,