> I'm running a few tests after upgrading a web application to 9.3.1. I have this issue where I am trying to get the documents modified since a certain date/time. However, even is a single document is modified db:list-details returns the same modified-date for all listed documents.

True; see earlier posts (e.g. [1]) for more details, or [2] for a
proposal to tackle this in future versions of BaseX.

[1] https://mailman.uni-konstanz.de/pipermail/basex-talk/2019-August/014621.html
[2] https://github.com/BaseXdb/basex/issues/988