All Feed URLs have changed. The show slug is not part of the URL any more. If you use Feedburner, remember to adjust the URL.
If you want your old URLs to work, you can add a manual redirect by adding some rules to your .htaccess:
# Pattern
Redirect 302 /feed/<show-slug>/<feed-slug>/ /feed/<feed-slug>/
# Examples
Redirect 302 /feed/cre/mp3/ /feed/mp3/
Redirect 302 /feed/cre/ogg/ /feed/ogg/
Redirect 302 /feed/cre/m4a/ /feed/m4a/
Go to Settings > Permalinks and hit Save Changes so WordPress recognizes the new custom URLs.
Please visit Podlove > Web Player and set the types again.