[icebraining]

It doesn't matter. Gmail does, and they block the feature for any sender which doesn't sign their emails.

https://developers.google.com/gmail/schemas/actions/securing...

[eps]

I routinely send emails through a mail server that doesn't sign them and they are delivered to Gmail recipients just fine.

[icebraining]

Sorry, I edited the post. They block that feature, not the whole mail.