After a revision, an old PDF link may redirect to an HTML page. That can be a useful successor if the requested information is available there in full. A successful redirect alone does not establish this.
Determine which version was replaced
Fictional example: an installation guide gets a new edition for a changed product model. The old guide still applies to earlier devices. Replacing it indiscriminately could give readers the wrong instructions.
Compare purpose, version and applicability. Ask the responsible person whether the old edition can be removed, must remain archived or has a clear successor. This is a content decision, not merely a URL correction.
Inspect the complete download route
Check the old public address, every redirect and the final response. A PDF destination should serve the correct file and content type. An HTML destination should make the relevant information available without another search.
Then update links on your own pages. A canonical response header can identify a preferred address among parallel copies; it does not replace a migration redirect when the old file has been withdrawn.
Record unresolved version questions in the mapping and settle them before removing the old document. A generic downloads index is suitable only if it genuinely meets the previous need.
Related check: Prioritise a redirect mapping.
If old download delivery is unclear, the Technology and stack review assesses technical responsibilities. Document content needs separate approval.