Send the following on WhatsApp
Continue to ChatPosteo (the secure email service) uses Roundcube as webmail software https://wp.jochen.hayek.name/blog-en/2019/03/29/posteo-roundcube/
Posteo (the secure email service) uses Roundcube as webmail software https://wp.jochen.hayek.name/blog-en/2019/03/29/posteo-roundcube/