https://www.sueddeutsche.de/digital/tutanota-verschluesselung-e-mail-ueberwachung-polizei-1.4676988
some clarification from - Tutanota team here. We came across this discussion and would like to clarify some points:
End-to-end encrypted emails are not affected.
End-to-end encrypted data (calendar, contacts, etc) are not affected.
This applies only to non-encrypted emails received/sent after the court has been issued.
A valid German court order is required for this, 4 have been issued in the first half of 2019.