Rated 2 out of 5 stars

4.4.1 Not working. After logging into google account, no calendars appear to choose from. Works fine on thunderbird 52.9.1 with version 3.3, when I downgraded.
I suggest people use the CALdav method, add CALdav calendar instead and write https://apidata.googleusercontent.com/caldav/v2/youremail@gmail.com/events as the address. Then you can also choose the mail account you want to associate it with. So that if you have any invitations, you can add them from your company e-mail with any domain name.

This review is for a previous version of the add-on (4.4.1).