Tag: https://github.com/apache/james-mime4j/releases/tag/apache-mime4j-project-0.8.12
Diff: https://github.com/apache/james-mime4j/compare/apache-mime4j-project-0.8.11...apache-mime4j-project-0.8.12

I've kept the tag and diff here, however I don't think they are correct see https://lists.apache.org/thread/q40qjdrxc65n8j991ph7m59trzjg6k17. I do think though that the MIME4J-327 issue is resolved. A reproducer I have for RESTEASY-3495 is fixed after the upgrade to 0.8.12.

The release mail thread, https://lists.apache.org/thread/70vlf454cobg2fhvlz7ym7rwwbf24018, seems to also indicate that MIME4J-327 was also fixed.