For non-service emails from Kontext, you can always unsubscribe it.
How to unsubscribe
For each email that can be unsubscribed, you can find an Unsubscribe link at the bottom of the email body.
Simply click Unsubscribe link to automatically remove you from the subscription list.
Alternatively, please send an email with details (newsletters, email address to unsubscribe) to unsub-newsletter[at]kontext.tech (please replace [at] with @).