For all of you podcasters out there, Apple has FINALLY enabled support for LetsEncrypt certificates to be used on your podcast feeds. I only recently ran into this issue standing up a new feed for The Talking Devs, and getting denied by the iTunes submit process (but accepted right away via Googles).
Apparently, this change also happened somewhat silently, and currently they (Apple) haven’t even updated their FAQ on the changes.
I learned about this via a friend, that pointed me to this article: https://feed.press/blog/2016/12/16/apple-silently-adds-support-lets-encrypt-certificates-podcast-feeds/
This post, "iTunes Podcast Feeds Now Support LetsEncrypt Certificates!", first appeared on https://www.codingwithcalvin.net/itunes-podcast-feeds-now-support-letsencrypt-certificates/