runtime.onUpdateAvailable

Fired when an update to the extension is available. This event enables an extension to delay an update: for example, because it is in the middle of some operation which should not be interrupted.

If the extension is not listening for this event when an update becomes available, the extension is reloaded immediately and the update is applied. If the extension is listening, then the update will be applied the next time the extension is reloaded. This happens if:

the browser is restarted
the extension is disabled and re-enabled
the extension explicitly reloads itself by calling runtime.reload().

Syntax

browser.runtime.onUpdateAvailable.addListener()
browser.runtime.onUpdateAvailable.removeListener(listener)
browser.runtime.onUpdateAvailable.hasListener(listener)

Events have three functions:

addListener(listener): Adds a listener to this event.
removeListener(listener): Stop listening to this event. The listener argument is the listener to remove.
hasListener(listener): Checks whether a listener is registered for this event. Returns true if it is listening, false otherwise.

addListener syntax

Parameters

listener

The function called when this event occurs. The function is passed this argument:

details: object. Contains a single property, a string named version, which represents the version number of the update.

Examples

Listen for UpdateAvailable events:

function handleUpdateAvailable(details) {
  console.log(details.version);
  // Proceed to upgrade the add-on
  browser.runtime.reload();
}

browser.runtime.onUpdateAvailable.addListener(handleUpdateAvailable);

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Firefox for Android	Safari on iOS
`onUpdateAvailable`	Chrome – Full support Chrome 25 (Release date: 2013-02-21) footnote Full support	Edge – Full support Edge 79 (Release date: 2020-01-15) footnote Full support	Firefox – Full support Firefox 51 (Release date: 2017-01-24) footnote Full support	Opera – Full support Opera 15 (Release date: 2013-07-02) footnote Full support	Safari – No support Safari footnote No support	Firefox for Android – Full support Firefox for Android 51 (Release date: 2017-01-24) footnote Full support	Safari on iOS – No support Safari on iOS footnote No support

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support

Note: This API is based on Chromium's chrome.runtime API. This documentation is derived from runtime.json in the Chromium code.

This page was last modified on Jul 17, 2025 by MDN contributors.

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