How do I let my chrome extension users know when the extension is updated?

I开发者_开发问答 want to show them a popup with the new features.

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I have submitted an answer and a working code example here chrome extension first run: Detect Chrome extension first run / update

You get the version from the manifest.json, you store that into your localStorage. In your background page, you check if your version has been set (via undefined) if it isn't set you know that your extension just installed, otherwise if the versions changed, you know it is being updating

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Store version variable in a localStorage and have local current_version variable hardcoded into javascript. Then during extension startup (in background.html) compare those two. After that update localStorage variable with the current version.