Our client uses Teams, we use Teams, and we communicate with each other using the original Skype for Business federation we had when we both used Skype for Busi

Our client uses Teams, we use Teams, and we communicate with each other using the original Skype for Business federation we had when we both used Skype for Business. All because my employer somehow doesn't support Teams federation (there are Teams groups with guest accounts, but that isn't the same because it requires you to switch context).