A relevant machine-translated paragraph appears to indicate that they are only required to implement monitoring of a single mailbox:
> This is about a blackmail that had been sent to an automotive supplier from a Tutanota mailbox. Tutanota is now forced to program a function by the end of the year that allows the State Criminal Police Office of North Rhine-Westphalia to monitor this mailbox.
Lacking the ability to read this without translation, I cannot determine conclusively whether or not they're also required to preemptively retain plaintext emails for other mailboxes in order to support any future wiretapping requests.
> This is about a blackmail that had been sent to an automotive supplier from a Tutanota mailbox. Tutanota is now forced to program a function by the end of the year that allows the State Criminal Police Office of North Rhine-Westphalia to monitor this mailbox.
Lacking the ability to read this without translation, I cannot determine conclusively whether or not they're also required to preemptively retain plaintext emails for other mailboxes in order to support any future wiretapping requests.