It seems 11.2 upgrade works fine but files missing for 11.1.
Code:
% sudo freebsd-update -v debug fetch
src component not installed, skipped
Looking up update.FreeBSD.org mirrors... 3 mirrors found.
Fetching public key from update2.freebsd.org... fetch: http://update2.freebsd.org/11.1-STABLE/amd64/pub.ssl: Not Found
failed.
Fetching public key from update1.freebsd.org... fetch: http://update1.freebsd.org/11.1-STABLE/amd64/pub.ssl: Not Found
failed.
Fetching public key from update4.freebsd.org... fetch: http://update4.freebsd.org/11.1-STABLE/amd64/pub.ssl: Not Found
failed.
No mirrors remaining, giving up.