Tolerated it and continued. The specification permits this but does not require it; a client that rejected it would also be conformant.
The client did what the clause requires.
What was measured
- Client
- quic-go — quic-go, quic-go v0.61.0
- Test
- PRIORITY_UPDATE sent by the server —
h-priority-update - Clause
- RFC 9218 §7.2 (MUST NOT)
- Class
- discretionary — The RFC permits either behaviour; the report says which was chosen.
- Required behaviour
- Reject it with H3_FRAME_UNEXPECTED, or ignore it — which is conformant depends on whether you implement extensible priorities at all, and that is not observable from here. A client that does implement RFC 9218 is bound by §7.2: servers "MUST NOT send PRIORITY_UPDATE frames of either type", and a client receiving one MUST treat it as a connection error of that type. A client that does not implement it sees frame type 0xf0700 as simply unknown, and RFC 9114 §9 requires unknown frame types to be ignored — so ignoring it is equally correct, for a different reason. Scoring this as a failure either way would accuse one of those two clients of a violation it did not commit, so the report says which answer was given rather than grading it.
- Measured
- 2026-09-18
Reproduce it
The suite is the judge, so the reproduction is to point the same client at the same test and let the server report what it saw.
SESSION=$(curl -sX POST https://conformance.pqcrypta.com/session | jq -r .id)
# then drive quic-go at the test URL and read the verdict:
curl -s https://conformance.pqcrypta.com/report/$SESSION.json | jq '.results["h-priority-update"]'