I’m new to add-on/extension development. I’ve inherited an add-on that uses manifest v2. Seems like the previous developer created the add-on for Chrome and was able to port it to Firefox. I’ve updated the manifest.json file to v3 and made the necessary code changes. I can install it in developer mode in Chrome and it works. However, in Firefox, when I try to install via about:debugging, I get an “Unsupported manifest version: 3” error. I also tried to install the add-on in the developer edition of Firefox and got the same result. Furthermore uploading a .crx file to https://www.extensiontest.com/ lists the manifest version as an error.
Is there a way to test an mv3 extension on Firefox? From what I read, we were suppose to be able to test mv3 extensions by the end of 2021 and the add-on store would accept mv3 extensions in early 2022. Is Firefox off schedule for testing and accepting mv3 extensions?