Err, why your you deliberately install years old software? And even more to the point why would you select a version that was never released to the public? Thunderbird went from 17 to 24 which was released September 17, 2013. I see the things you use as reasons. But they neither support your ancient version choice, not do they explain why you would be wanting to use the addon with that version. TBSync supports the current release version of 102. per it's download site. https://addons.thunderbird.net/en-us/thunderbird/addon/tbsync/?src=userprofile It does not support calendars with google, but the page contains a link for that that need google tasks as Thunderbird has natively supported caldav calendars from google for about 10 years. But it was only in recent version it got a slick wizard to guide you. The provider is, as far as I am aware, the only source of google tasks in Thunderbird. https://addons.thunderbird.net/en-US/thunderbird/addon/provider-for-google-calendar/ Personally I do not use the google tasks, so I use the inbuilt Thunderbird caldav to access and sync my calendar at google. This is accessed from the menu > new > calendar. Enter the details of username in the wizard (no URL/Location is required. It will auto fill with a grey google.com text.) and the wizard will fetch a list of available calendars from the server for you to select from. To access your contacts, open the address book and click the down arrow beside the New address book item. Select add a carddav address book. Again follow the prompts to set up a new syncronised address book in the address book list which will be named Google with the email address it links to as the name.