These aren&#x27;t requirements.  Gmail is a mail client.  What it is doing is adding warnings.<p>Without SPF&#x2F;DKIM you can&#x27;t be authenticated.  Google is showing the user that they cannot verify the sender.<p>Without TLS email is sent in the clear.  Google is showing the user that sensitive information will be visible when sent over the network.<p>You can run your server fine without this, but users will be warned that you&#x27;re not following best practices.<p>It is not Gmail&#x27;s fault that you&#x27;re late to best practices.