The Enhanced plan reads:

> We rate limit users and domains to 300 outbound SMTP messages per 1 day.

People who are using DeltaChat groups should think twice here: Every time you reply to the group it will “cost you” as many outgoing emails as there are people in the group, and every time you read a group message it will also cost you as many outgoing emails as there are group members because “read receipts” are sent as plain emails.

A couple of years ago I had to switch email provider exactly because of this. While 300 outgoing emails may sound like a lot, it isn't if you're using DeltaChat groups.