I used to be able to sort collections based on if there was an attachment (PDF) or not. For some reason this does not work anymore with the new version.

It was extremely handy for systematising PDF collection, after getting a bunch of references from e.g. Scopus.

Also, is there a way to automagically combine old and new entries that have e.g. the same DOI? This would be useful in making systematic lit reviews, when one already has some of the papers in zotero. Duplicate entries are a huge issue.