Personal data generally is to be deleted when the intended usage is over. Simultaneously with this obligation to delete, there is the burden of proof in the context of judicial or extrajudicial disputes, e.g. for the evidence of an opt-in or the intended use of the data. This means there is a legitimate interest, with a duration of 36 months after sending the last message (limitation period), to save personal data for the proof of intended usage.
For more information, we link to this document of the Certified Senders Alliance (CSA): Obligation to Delete vs. Burden of Proof. https://certified-senders.org/wp-content/uploads/2018/09/Obligation-to-Delete-vs-Burden-of-Proof.pdf
Therefore, the data saved in promio.connect is subject to these standard deleting rules:
These standard deleting rules are the minimum–differing, stricter rules can be defined for each client. The following processes are possible: