The following features have been deprecated for well over the 2
release cycle we promise
``-usbdevice`` (since 2.10.0)
``-drive file=3Djson:{...{'driver':'file'}}`` (since 3.0)
``-vnc acl`` (since 4.0.0)
``-mon ...,control=3Dreadline,pretty=3Don|off`` (since 4.1)
``migrate_set_downtime`` and ``migrate_set_speed`` (since 2.8.0)
``query-named-block-nodes`` result ``encryption_key_missing`` (since 2.10.0)
``query-block`` result ``inserted.encryption_key_missing`` (since 2.10.0)
``migrate-set-cache-size`` and ``query-migrate-cache-size`` (since 2.11.0)
``query-named-block-nodes`` and ``query-block`` result dirty-bitmaps[i].sta=
tus (ince 4.0)
``query-cpus`` (since 2.12.0)
``query-cpus-fast`` ``arch`` output member (since 3.0.0)
``query-events`` (since 4.0)
chardev client socket with ``wait`` option (since 4.0)
``acl_show``, ``acl_reset``, ``acl_policy``, ``acl_add``, ``acl_remove`` (s=
ince 4.0.0)
``ide-drive`` (since 4.2)
``scsi-disk`` (since 4.2)
AFAICT, libvirt has ceased to use all of these too.