I have close to 900 references from ArXiv in my library. I know that some of these papers have been updated since I last added them. I have been checking the URLs manually whenever I need to cite one of these papers to ensure that the version I have is the most current.
When I tried to use EndNote to search for reference updates for all the papers in ArXiv in my library, it finds other places where certain articles are published, but it does not find updates on ArXiv itself.
ArXiv has a structured format in which article updates are indicated on the article’s abstract page just above the title. It should be easy to integrate a functionality into EndNote to see when an article was added to a user’s library and whether the date it was last modified in ArXiv is later than that date (i.e. the article in the library needs to be updated).
The same type of process should be done for other preprint sites such as the IACR’s e-print Archive, especially considering that many of these papers are corrected, updated, or withdrawn after the official publications come out.