So.. I got an "A" rating but not 100% in all categories. Is there any way I can improve on this (nginx)?

I have a lot of users with older browsers so that's really important, not sure if that matters.

ssl_ciphers ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL:!EDH;