root@Bebop:~ # freebsd-update -r 11.0-RELEASE upgrade
Looking up update.FreeBSD.org mirrors... 4 mirrors found.
Fetching metadata signature for 10.3-RELEASE from update6.freebsd.org... done.
Fetching metadata index... done.
Inspecting system... y
done.

The following components of FreeBSD seem to be installed:
kernel/generic src/src world/base world/doc world/games world/lib32

The following components of FreeBSD do not seem to be installed:

Does this look reasonable (y/n)?
Fetching metadata signature for 11.0-RELEASE from update6.freebsd.org... done.
Fetching metadata index... done.

The update metadata is correctly signed, but
failed an integrity check.
Cowardly refusing to proceed any further.
root@Bebop:~ #