Oh thanks, didn't realize there were partial update packages. This can be closed as not-a-bug, or maybe the "bug" is "clarify in the --help output what --apply-update does".

--apply-update flag expects a .zip, but headless server updates are now distributed as a .tar.xz

Relevant snippet from my journalctl:


Oct 24 15:28:39 Unit-02 factorio[53313]: 0.382 Info Updater.cpp:286: Applying update /tmp/factorio_update.tar.xz
Oct 24 15:28:39 Unit-02 factorio[53313]: 0.383 ...