Support the OCSP Must Staple TLS Extension
As described in this post by Mozilla:
OCSP Must-Staple makes use of the recently specified TLS Feature Extension. When a CA adds this extension to a certificate, it requires the browser to ensure a stapled OCSP response is present in the TLS handshake. If an OCSP response is not present, the connection will fail and the browser will display a non-overridable error page.