Updating the Podcast Feed iTunes Checks
If you're unable to create a 301 redirection on your RSS feed, you should at least specify the new feed URL via the appropriate iTunes tag.
The tag is called:
In your old feed, for the new feed URL tag, enter the NEW location of your feed. For example: https://feed.mynewfeed.com
This tag will let the iTunes podcast directory know that it should look to the new feed URL location for updates.