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A community-driven Web developer engagement initiative focused on the backward compatibility in Firefox. Documents, tools, latest updates & more.

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Mozilla shipped Firefox 81 Beta and Developer Edition today.

If you have any worker script on your site, be reminded that the MIME type enforcement, one of the changes being postponed due to the COVID-19 pandemic, is shipping with Firefox 81. While other changes are relatively minor, take a moment to check out the six compatibility notes for the new release that will be out of beta in late September.

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