I often initially download/import a paper when it is posted to a preprint server such as bioRxiv. I would like to be able to check for updates to the pre-print and be able to download the published version when it is eventually peer-reviewed (which is typically noted on the paper's bioRxiv page along with a link to the published version). Currently, when I import the published version, it is marked a new, different publication-- likely due to differing metadata on fields such as journal, volume, etc.
It would be great to be able to either directly add the new file to the existing paper like you are able to do when you refresh/update metadata or to be able to manually link the two as you could previously do with Papers3's detect and merge duplicates function.
I'm looking forward to see this implemented in readcube/paper