Old episodes after podcast redirect

The iTunes Store/Apple Podcasts 'Browse' reads what's in the feed. If you transfer the Store to a new feed, then any episodes which are in the old feed but not in the new feed will disappear. For existing subscribers, such episodes will disappear unless they have been downloaded (though that would normally be the case) - of course new suscribers won't see the missing episodes.

Moving the Store to using a new feed has to be accomplished by the proper methods if you want to avoid problems. This page explains the process in detail:

http://wilmut.uk/move

Note that the two methods which will also redirect your existing subscribers require access to the coding of the feed, or to the server (to set up a redirect), both of which may be difficult with SoundCloud. You can redirect the feed from your page on Podcasts Connect but this will only redirect the Store: existing subscribers won't see any new episodes. You could of course make an announcement telling them to resubscribe.