Join Teams work meetings from Microsoft Teams (free) and vice versa

Microsoft Teams (Free) users can currently join Teams for work (or school) meetings only as guests, which requires them to use a browser and results in a sub-optimal experience. The new feature rolling out will allow these users to join Teams for work (or school) meetings in one click, without being redirected to the browser or asked to fill in their name/surname. They will also be able to continue collaborating with the meeting organizer and other participants via meeting chat after the meeting.  The feature will work in the opposite way as well, so Teams for work (or school) will just as easily be able to join meetings hosted by a Teams Free user with one click. This is associated with Roadmap ID: 167326

Backup-sfb has been updated to support 2019

I really didn't think I'd do it, but given the ammount of requests for it and a verification of versions included in Skype for Business 2019. I have decided to "officially" update my Backup script to SFB 2019.
It has not been thoroughly tested by me (as I don't have any customers using sfb2019 yet), and there is no guarantee it will back up everything. Feedback and suggestions are of course very welcome!

The script is also no longer signed. If I do get around to buy a new certificate, I might sign it again in the future.

As before, the script can be found at the technet gallery (link)