App version: x.y.z (state whether from Google Play/F-Droid/Custom built APK)
3.6.0
Problem you may be having, or feature you want:
Some podcasts clean up older episodes on a semi regular basis, some delete small announcement episodes (illness, events) which causes unnecessary failed attempts to download things.
Suggested solution:
Every now and then do a http HEAD request and check if files are available on the other side and store the result and make an icon in the episode list to mark it as “downloadable/unavailable”
Compare this with the episode publish date and let a heuristic also see if there is a pattern.