In the mobile app as well as in the web app you can find the setting called: Staying in touch. When activated you receive news from us on offers, etc. If you rather not get news from us you can opt out. All you need to do is to deactivate this setting.
Keep in mind that the opt-out option is for offers and news only and does not cover any messaging we consider essential, such as information on scheduled downtime of our servers in view of maintenance, information on the free trial, required firmware, and/or app updates.
Moreover, if you are subscribed to a subscription plan you receive your invoice as well as confirmation emails on changes and/or cancellation irrespective whether you opted-out or not.
You can find this setting in the mobile app under the Application Settings (gear icon top right corner). In the web app the option is listed under My Account (click the Head icon in the top right corner and select My Account from the drop-list).