EU-PMC has posted some information on how it is going to display notices of withdrawals of preprints - http://blog.europepmc.org/2021/12/transparency-for-preprints.html.
The metadata is carried under the "PUB_TYPE" tag (though one might argue that the state change is more to do with an action on a particularly type of publication, rather than rendering a publication into a particular type).
It does mention that some archives overwrite the metadata of items, if they are withdrawn rather than issuing a new item cap-stoning the thread.
Furthermore they say
"We rely on manual analysis of the flagged preprint full text to discover that it contains a removal or withdrawal notice, with a follow-up manual check on the preprint server. In the future, we hope that preprint servers will share the withdrawal/removal status in a machine readable format, potentially through a single service, such as Crossref, which would allow us and other providers to automate updates to the preprint record"
This latter point is an interesting one to me. What would it take to created an automated federated notification system for these kinds of changes. Many years ago, in the distant past of an earlier kinder (so we thought) version of the internets I though PubSubHubBub could play a role here. Now it looks like the centralised mechanism - e.g. CrossRef - is more likely to be the way to go.
The metadata is carried under the "PUB_TYPE" tag (though one might argue that the state change is more to do with an action on a particularly type of publication, rather than rendering a publication into a particular type).
It does mention that some archives overwrite the metadata of items, if they are withdrawn rather than issuing a new item cap-stoning the thread.
Furthermore they say
"We rely on manual analysis of the flagged preprint full text to discover that it contains a removal or withdrawal notice, with a follow-up manual check on the preprint server. In the future, we hope that preprint servers will share the withdrawal/removal status in a machine readable format, potentially through a single service, such as Crossref, which would allow us and other providers to automate updates to the preprint record"
This latter point is an interesting one to me. What would it take to created an automated federated notification system for these kinds of changes. Many years ago, in the distant past of an earlier kinder (so we thought) version of the internets I though PubSubHubBub could play a role here. Now it looks like the centralised mechanism - e.g. CrossRef - is more likely to be the way to go.