feat(quic): deprecate QUIC draft-29 version support

transports/quic/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 <!-- Update to libp2p-core v0.43.0 -->
 
+- Deprecate `Config::support_draft_29`.
+  See [PR 5786](https://github.com/libp2p/rust-libp2p/pull/5786).
+
 ## 0.11.1
 
 - Update `libp2p-tls` to version `0.5.0`, see [PR 5547]

transports/quic/src/config.rs

@@ -59,6 +59,7 @@ pub struct Config {
     /// If support for draft-29 is enabled servers support draft-29 and version 1 on all
     /// QUIC listening addresses.
     /// As client the version is chosen based on the remote's address.
+    #[deprecated(note = "QUIC draft versions are no longer supported")]
     pub support_draft_29: bool,
 
     /// TLS client config for the inner [`quinn::ClientConfig`].
@@ -72,6 +73,7 @@ pub struct Config {
     mtu_discovery_config: Option<MtuDiscoveryConfig>,
 }
 
+#[expect(deprecated)]
 impl Config {
     /// Creates a new configuration object with default values.
     pub fn new(keypair: &libp2p_identity::Keypair) -> Self {
@@ -122,6 +124,7 @@ pub(crate) struct QuinnConfig {
     pub(crate) endpoint_config: quinn::EndpointConfig,
 }
 
+#[expect(deprecated)]
 impl From<Config> for QuinnConfig {
     fn from(config: Config) -> QuinnConfig {
         let Config {

transports/quic/src/transport.rs

@@ -84,6 +84,7 @@ pub struct GenTransport<P: Provider> {
     hole_punch_attempts: HashMap<SocketAddr, oneshot::Sender<Connecting>>,
 }
 
+#[expect(deprecated)]
 impl<P: Provider> GenTransport<P> {
     /// Create a new [`GenTransport`] with the given [`Config`].
     pub fn new(config: Config) -> Self {

transports/quic/tests/smoke.rs

@@ -295,6 +295,7 @@ fn concurrent_connections_and_streams_tokio() {
         .quickcheck(prop::<quic::tokio::Provider> as fn(_, _) -> _);
 }
 
+#[expect(deprecated)]
 #[cfg(feature = "tokio")]
 #[tokio::test]
 async fn draft_29_support() {