If you’ve ever wondered which security protocols your email-provider supports, there is an easy way that I found via Mastodon:
The European Commision provides My Email Communications Security Assessment (MECSA) (https://mecsa.jrc.ec.europa.eu/) with which you can quickly check, which of the protocols your provider supports (StartTLS, x509 Ceerts, SPF, DKIM, DMARC, DANE, DNSSEC).
MECSA is an online tool developed by the Joint Research Centre (JRC) to assess the security of email communication between providers.
By following a simple procedure, MECSA will allow you to better understand the technical capacity of your email provider to protect the security and privacy of your email communications.