topic Provisional
Verified 2026-09-19 · registry updated 2023-06-13

HTTP registry: 0x4d

Registered value from the IANA HTTP registry.

HTTP/3 registry values apply to QUIC-backed streams, frames, settings, or protocol negotiation. The registry marks this value provisional; review compatibility before deploying it. 0x4d is provisional in HTTP/3 Frame Types. Defining reference: draft-beky-httpbis-metadata-02.

httpregistryhttp3-parametershttp3-parameters-frame-types

Identifier (http)

0x4d

Registered value from the IANA HTTP registry.

Preserve HTTP semantics while accounting for QUIC migration, TLS/ALPN negotiation, and early-data replay risk. The registry marks this value provisional; review compatibility before deploying it.

This registry value is currently marked provisional by IANA. Follow the defining specification before sending, accepting, or proxying it.

IANA registry: http3-parameters/http3-parameters-frame-types

Registry reference: draft-beky-httpbis-metadata-02

Permalink: https://merginit.com/reference/http/registry/http3-parameters/http3-parameters-frame-types/0x4d-267