Why does my podcast suddenly have no items in iTunes after switching to Feedburner?

Question

We recently switched our podcast over to using Feedburner as a proxy to our original RSS feed. Shortly thereafter, iTunes started showing 0 episodes.

Here's our original RSS feed:

http://www.esvbible.org/devotions/rss/chronological/

Here's our Feedburnerized feed:

http://feeds.feedburner.com/ESV-Chronological

Here's the podcast page on Apple's site:

http://itunes.apple.com/us/podcast/esv-chronological/id301024126

The enclosures are still there, with the appropriate type. Feedburner has changed the length of the enclosure from the empty string to "0", which after checking the spec is technically correct.

Answer 1

Turns out, iTunes completely ignores the MIME type, and is dependent upon the .mp3 file extension in the URL. Adding the extension fixes the feed.