diff --git a/.clippy.toml b/.clippy.toml
index b3c3a24..4972822 100644
--- a/.clippy.toml
+++ b/.clippy.toml
@@ -1 +1 @@
-msrv = "1.63.0"
+msrv = "1.85.0"
diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index c19dc00..2f63fd1 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -10,26 +10,29 @@ env:
   CARGO_TERM_COLOR: always
   RUST_BACKTRACE: 1
 
-# This fork ships one configuration: the rust-hpke backend with the secp256k1 DHKEM
-# from bitcoin-hpke, on stable Rust. That is what CI gates.
+# This fork ships the rust-hpke backend with the secp256k1 DHKEM from bitcoin-hpke.
 #
 # Not in the matrix, on purpose:
 # - nss: NSS has no secp256k1 DHKEM, and the backend has not compiled since the Kem
 #   enum was pruned to K256Sha256 (bac8f2c). Drop or delete is a separate decision.
-# - an MSRV toolchain: the declared MSRV cannot resolve current transitive
-#   dependencies. Restore the leg when #6 is settled.
 
 jobs:
   check:
-    name: Continuous Integration (rust-hpke, stable)
+    name: Continuous Integration (rust-hpke)
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        rust:
+          - 1.85.0 # MSRV
+          - stable
     steps:
       - uses: actions/checkout@v4
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: stable
+          toolchain: ${{ matrix.rust }}
           components: rustfmt, clippy
 
       - name: Build
diff --git a/Cargo.toml b/Cargo.toml
index 0621518..9c9026e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,5 @@
 [workspace]
-resolver = "2"
+resolver = "3"
 members = [
   "bhttp",
   "bhttp-convert",
diff --git a/README.md b/README.md
index 3972f29..fbdb2b5 100644
--- a/README.md
+++ b/README.md
@@ -138,4 +138,4 @@ install itself.
 
 ## Minnimum Supported Rust Version (MSRV)
 
-`ohttp` and `bhttp` should compile on Rust 1.63.0.
+`ohttp` and `bhttp` should compile on Rust 1.85.0.
diff --git a/bhttp-convert/Cargo.toml b/bhttp-convert/Cargo.toml
index 8a82101..7a18aae 100644
--- a/bhttp-convert/Cargo.toml
+++ b/bhttp-convert/Cargo.toml
@@ -2,7 +2,7 @@
 name = "bhttp-convert"
 version = "0.5.3"
 authors = ["Martin Thomson <mt@lowentropy.net>"]
-edition = "2021"
+edition = "2024"
 
 [dependencies]
 structopt = "0.3"
diff --git a/bhttp/Cargo.toml b/bhttp/Cargo.toml
index 8c89536..cfd8e13 100644
--- a/bhttp/Cargo.toml
+++ b/bhttp/Cargo.toml
@@ -2,8 +2,8 @@
 name = "bhttp"
 version = "0.5.3"
 authors = ["Martin Thomson <mt@lowentropy.net>"]
-edition = "2021"
-rust-version = "1.63.0"
+edition = "2024"
+rust-version = "1.85.0"
 license = "MIT OR Apache-2.0"
 description = "Binary HTTP messages (RFC 9292)"
 repository = "https://github.com/martinthomson/ohttp"
@@ -21,5 +21,7 @@ write-http = []
 thiserror = "1"
 url = {version = "2", optional = true}
 
+yoke-derive = "=0.8.2"
+
 [dev-dependencies]
 hex = "0.4"
diff --git a/bhttp/src/lib.rs b/bhttp/src/lib.rs
index 3c8fbde..d84b2f3 100644
--- a/bhttp/src/lib.rs
+++ b/bhttp/src/lib.rs
@@ -31,8 +31,8 @@ pub use err::Error;
 ))]
 use err::Res;
 #[cfg(feature = "read-http")]
-use parse::{downcase, is_ows, read_line, split_at, COLON, SEMICOLON, SLASH, SP};
-use parse::{index_of, trim_ows, COMMA};
+use parse::{COLON, SEMICOLON, SLASH, SP, downcase, is_ows, read_line, split_at};
+use parse::{COMMA, index_of, trim_ows};
 #[cfg(feature = "read-bhttp")]
 use rw::{read_varint, read_vec};
 #[cfg(feature = "write-bhttp")]
@@ -401,11 +401,7 @@ impl ControlData {
     #[must_use]
     pub fn path(&self) -> Option<&[u8]> {
         if let Self::Request { path, .. } = self {
-            if path.is_empty() {
-                None
-            } else {
-                Some(path)
-            }
+            if path.is_empty() { None } else { Some(path) }
         } else {
             None
         }
diff --git a/bhttp/src/rw.rs b/bhttp/src/rw.rs
index 92009ed..a761f2b 100644
--- a/bhttp/src/rw.rs
+++ b/bhttp/src/rw.rs
@@ -4,7 +4,7 @@ use std::{convert::TryFrom, io};
 
 use crate::err::Res;
 #[cfg(feature = "read-bhttp")]
-use crate::{err::Error, ReadSeek};
+use crate::{ReadSeek, err::Error};
 
 #[cfg(feature = "write-bhttp")]
 #[allow(clippy::cast_possible_truncation)]
diff --git a/ohttp-client-cli/Cargo.toml b/ohttp-client-cli/Cargo.toml
index 2a99603..51b395f 100644
--- a/ohttp-client-cli/Cargo.toml
+++ b/ohttp-client-cli/Cargo.toml
@@ -2,7 +2,7 @@
 name = "ohttp-client-cli"
 version = "0.5.3"
 authors = ["Martin Thomson <mt@lowentropy.net>"]
-edition = "2021"
+edition = "2024"
 
 [features]
 default = ["rust-hpke"]
diff --git a/ohttp-client-cli/src/main.rs b/ohttp-client-cli/src/main.rs
index 7acc0f1..204f2b4 100644
--- a/ohttp-client-cli/src/main.rs
+++ b/ohttp-client-cli/src/main.rs
@@ -1,7 +1,7 @@
 #![deny(warnings, clippy::pedantic)]
 
 use bhttp::{Message, Mode};
-use ohttp::{init, ClientRequest};
+use ohttp::{ClientRequest, init};
 use std::io::{self, BufRead, Write};
 
 fn main() {
diff --git a/ohttp-client/Cargo.toml b/ohttp-client/Cargo.toml
index 75d59e0..4d5df17 100644
--- a/ohttp-client/Cargo.toml
+++ b/ohttp-client/Cargo.toml
@@ -2,7 +2,7 @@
 name = "ohttp-client"
 version = "0.5.3"
 authors = ["Martin Thomson <mt@lowentropy.net>"]
-edition = "2021"
+edition = "2024"
 
 [features]
 default = ["rust-hpke"]
diff --git a/ohttp-server/Cargo.toml b/ohttp-server/Cargo.toml
index 8e4581c..3bb0eb7 100644
--- a/ohttp-server/Cargo.toml
+++ b/ohttp-server/Cargo.toml
@@ -2,7 +2,7 @@
 name = "ohttp-server"
 version = "0.5.3"
 authors = ["Martin Thomson <mt@lowentropy.net>"]
-edition = "2021"
+edition = "2024"
 
 [features]
 default = ["rust-hpke"]
diff --git a/ohttp-server/src/main.rs b/ohttp-server/src/main.rs
index 7c33b20..7acbead 100644
--- a/ohttp-server/src/main.rs
+++ b/ohttp-server/src/main.rs
@@ -9,8 +9,8 @@ use std::{
 
 use bhttp::{Message, Mode, StatusCode};
 use ohttp::{
-    hpke::{Aead, Kdf, Kem},
     KeyConfig, Server as OhttpServer, SymmetricSuite,
+    hpke::{Aead, Kdf, Kem},
 };
 use structopt::StructOpt;
 use warp::Filter;
diff --git a/ohttp/Cargo.toml b/ohttp/Cargo.toml
index 73cdfed..e6de02d 100644
--- a/ohttp/Cargo.toml
+++ b/ohttp/Cargo.toml
@@ -2,8 +2,8 @@
 name = "bitcoin-ohttp"
 version = "0.6.0"
 authors = ["Dan Gould <d@ngould.dev>"]
-edition = "2021"
-rust-version = "1.63.0"
+edition = "2024"
+rust-version = "1.85.0"
 build = "build.rs"
 license = "MIT OR Apache-2.0"
 description = "Oblivious HTTP over secp256k1 and ChaCha20Poly1305"
diff --git a/ohttp/build.rs b/ohttp/build.rs
index 1c01e3f..57e93df 100644
--- a/ohttp/build.rs
+++ b/ohttp/build.rs
@@ -473,7 +473,9 @@ mod nss {
                 "NSS_DIR path (obtained via `env`) does not exist: {}",
                 nss_dir.display()
             );
-            panic!("It looks like NSS is not built. Please run `libs/verify-[platform]-environment.sh` in application-services first!");
+            panic!(
+                "It looks like NSS is not built. Please run `libs/verify-[platform]-environment.sh` in application-services first!"
+            );
         }
 
         let lib_dir = nss_dir.join("lib");
diff --git a/ohttp/src/config.rs b/ohttp/src/config.rs
index 0e6d747..14448ad 100644
--- a/ohttp/src/config.rs
+++ b/ohttp/src/config.rs
@@ -1,7 +1,7 @@
 use crate::{
+    KeyId,
     err::{Error, Res},
     hpke::{Aead as AeadId, Kdf, Kem},
-    KeyId,
 };
 use byteorder::{NetworkEndian, ReadBytesExt, WriteBytesExt};
 use std::{
@@ -11,13 +11,13 @@ use std::{
 
 #[cfg(feature = "nss")]
 use crate::nss::{
-    hpke::{generate_key_pair, Config as HpkeConfig, HpkeR},
     PrivateKey, PublicKey,
+    hpke::{Config as HpkeConfig, HpkeR, generate_key_pair},
 };
 
 #[cfg(feature = "rust-hpke")]
 use crate::rh::hpke::{
-    derive_key_pair, generate_key_pair, Config as HpkeConfig, HpkeR, PrivateKey, PublicKey,
+    Config as HpkeConfig, HpkeR, PrivateKey, PublicKey, derive_key_pair, generate_key_pair,
 };
 
 /// A tuple of KDF and AEAD identifiers.
@@ -278,8 +278,9 @@ impl AsRef<Self> for KeyConfig {
 #[cfg(test)]
 mod test {
     use crate::{
+        Error, KeyConfig, KeyId, SymmetricSuite,
         hpke::{Aead, Kdf, Kem},
-        init, Error, KeyConfig, KeyId, SymmetricSuite,
+        init,
     };
     use std::iter::zip;
 
diff --git a/ohttp/src/lib.rs b/ohttp/src/lib.rs
index b047c5a..b0e4bc1 100644
--- a/ohttp/src/lib.rs
+++ b/ohttp/src/lib.rs
@@ -313,10 +313,10 @@ impl ClientResponse {
 #[cfg(all(test, feature = "client", feature = "server"))]
 mod test {
     use crate::{
+        ClientRequest, Error, KeyConfig, KeyId, Server,
         config::SymmetricSuite,
         err::Res,
         hpke::{Aead, Kdf, Kem},
-        ClientRequest, Error, KeyConfig, KeyId, Server,
     };
     use log::trace;
     use std::{fmt::Debug, io::ErrorKind};
diff --git a/ohttp/src/nss/aead.rs b/ohttp/src/nss/aead.rs
index 18f0b66..288ae13 100644
--- a/ohttp/src/nss/aead.rs
+++ b/ohttp/src/nss/aead.rs
@@ -1,12 +1,12 @@
 use super::{
     err::secstatus_to_res,
     p11::{
+        Item, SymKey,
         sys::{
-            self, PK11Context, PK11_AEADOp, PK11_CreateContextBySymKey, PRBool, CKA_DECRYPT,
+            self, CK_ATTRIBUTE_TYPE, CK_GENERATOR_FUNCTION, CK_MECHANISM_TYPE, CKA_DECRYPT,
             CKA_ENCRYPT, CKA_NSS_MESSAGE, CKG_GENERATE_COUNTER_XOR, CKG_NO_GENERATE, CKM_AES_GCM,
-            CKM_CHACHA20_POLY1305, CK_ATTRIBUTE_TYPE, CK_GENERATOR_FUNCTION, CK_MECHANISM_TYPE,
+            CKM_CHACHA20_POLY1305, PK11_AEADOp, PK11_CreateContextBySymKey, PK11Context, PRBool,
         },
-        Item, SymKey,
     },
 };
 use crate::{
@@ -195,7 +195,7 @@ impl Aead {
 mod test {
     use super::{
         super::{super::hpke::Aead as AeadId, init},
-        Aead, Mode, SequenceNumber, NONCE_LEN,
+        Aead, Mode, NONCE_LEN, SequenceNumber,
     };
 
     /// Check that the first invocation of encryption matches expected values.
diff --git a/ohttp/src/nss/err.rs b/ohttp/src/nss/err.rs
index af85066..5c7a83d 100644
--- a/ohttp/src/nss/err.rs
+++ b/ohttp/src/nss/err.rs
@@ -88,8 +88,8 @@ pub fn secstatus_to_res(rv: SECStatus) -> Res<()> {
 #[cfg(test)]
 mod tests {
     use super::{
-        super::{init, SECFailure, SECSuccess},
-        secstatus_to_res, PRErrorCode, PR_SetError,
+        super::{SECFailure, SECSuccess, init},
+        PR_SetError, PRErrorCode, secstatus_to_res,
     };
 
     fn set_error_code(code: PRErrorCode) {
diff --git a/ohttp/src/nss/hkdf.rs b/ohttp/src/nss/hkdf.rs
index 470b1dd..6ef95e5 100644
--- a/ohttp/src/nss/hkdf.rs
+++ b/ohttp/src/nss/hkdf.rs
@@ -1,12 +1,12 @@
 use super::{
     super::hpke::{Aead, Kdf},
     p11::{
+        ParamItem, SymKey,
         sys::{
-            self, CKA_DERIVE, CKF_HKDF_SALT_DATA, CKF_HKDF_SALT_NULL, CKM_AES_GCM,
-            CKM_CHACHA20_POLY1305, CKM_HKDF_DATA, CKM_HKDF_DERIVE, CKM_SHA256, CK_BBOOL,
-            CK_HKDF_PARAMS, CK_INVALID_HANDLE, CK_MECHANISM_TYPE, CK_OBJECT_HANDLE, CK_ULONG,
+            self, CK_BBOOL, CK_HKDF_PARAMS, CK_INVALID_HANDLE, CK_MECHANISM_TYPE, CK_OBJECT_HANDLE,
+            CK_ULONG, CKA_DERIVE, CKF_HKDF_SALT_DATA, CKF_HKDF_SALT_NULL, CKM_AES_GCM,
+            CKM_CHACHA20_POLY1305, CKM_HKDF_DATA, CKM_HKDF_DERIVE, CKM_SHA256,
         },
-        ParamItem, SymKey,
     },
 };
 use crate::err::Res;
diff --git a/ohttp/src/nss/hpke.rs b/ohttp/src/nss/hpke.rs
index b7ef845..3a9034a 100644
--- a/ohttp/src/nss/hpke.rs
+++ b/ohttp/src/nss/hpke.rs
@@ -1,7 +1,7 @@
 use super::{
     super::hpke::{Aead, Kdf, Kem},
-    err::{sec::SEC_ERROR_INVALID_ARGS, secstatus_to_res, Error},
-    p11::{sys, Item, PrivateKey, PublicKey, Slot, SymKey},
+    err::{Error, sec::SEC_ERROR_INVALID_ARGS, secstatus_to_res},
+    p11::{Item, PrivateKey, PublicKey, Slot, SymKey, sys},
 };
 use crate::err::Res;
 use log::{log_enabled, trace};
@@ -292,7 +292,7 @@ pub fn generate_key_pair(kem: Kem) -> Res<(PrivateKey, PublicKey)> {
 
 #[cfg(test)]
 mod test {
-    use super::{generate_key_pair, Config, HpkeContext, HpkeR, HpkeS};
+    use super::{Config, HpkeContext, HpkeR, HpkeS, generate_key_pair};
     use crate::{hpke::Aead, init};
 
     const INFO: &[u8] = b"info";
diff --git a/ohttp/src/nss/mod.rs b/ohttp/src/nss/mod.rs
index 1b60c9e..626a11e 100644
--- a/ohttp/src/nss/mod.rs
+++ b/ohttp/src/nss/mod.rs
@@ -11,9 +11,9 @@ pub mod aead;
 pub mod hkdf;
 pub mod hpke;
 
-pub use self::p11::{random, PrivateKey, PublicKey};
-use err::secstatus_to_res;
+pub use self::p11::{PrivateKey, PublicKey, random};
 pub use err::Error;
+use err::secstatus_to_res;
 use lazy_static::lazy_static;
 use std::ptr::null;
 
diff --git a/ohttp/src/nss/p11.rs b/ohttp/src/nss/p11.rs
index 9bddef6..c87cbe9 100644
--- a/ohttp/src/nss/p11.rs
+++ b/ohttp/src/nss/p11.rs
@@ -4,7 +4,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use super::err::{secstatus_to_res, Error};
+use super::err::{Error, secstatus_to_res};
 use crate::err::Res;
 use std::{
     convert::TryFrom,
@@ -28,11 +28,11 @@ pub mod sys {
 }
 
 use sys::{
-    PK11ObjectType, PK11SlotInfo, PK11SymKey, PK11_ExtractKeyValue, PK11_FreeSlot, PK11_FreeSymKey,
+    CK_ATTRIBUTE_TYPE, CKA_VALUE, PK11_ExtractKeyValue, PK11_FreeSlot, PK11_FreeSymKey,
     PK11_GenerateRandom, PK11_GetInternalSlot, PK11_GetKeyData, PK11_ReadRawAttribute,
-    PK11_ReferenceSymKey, PRBool, SECITEM_FreeItem, SECItem, SECItemType, SECKEYPrivateKey,
-    SECKEYPublicKey, SECKEY_DestroyPrivateKey, SECKEY_DestroyPublicKey, CKA_VALUE,
-    CK_ATTRIBUTE_TYPE,
+    PK11_ReferenceSymKey, PK11ObjectType, PK11SlotInfo, PK11SymKey, PRBool, SECITEM_FreeItem,
+    SECItem, SECItemType, SECKEY_DestroyPrivateKey, SECKEY_DestroyPublicKey, SECKEYPrivateKey,
+    SECKEYPublicKey,
 };
 
 macro_rules! scoped_ptr {
diff --git a/ohttp/src/rand.rs b/ohttp/src/rand.rs
index 381b83f..8e70938 100644
--- a/ohttp/src/rand.rs
+++ b/ohttp/src/rand.rs
@@ -4,7 +4,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use ::rand::{thread_rng, RngCore};
+use ::rand::{RngCore, thread_rng};
 
 #[must_use]
 pub fn random(size: usize) -> Vec<u8> {
diff --git a/ohttp/src/rh/aead.rs b/ohttp/src/rh/aead.rs
index f209086..b89c96e 100644
--- a/ohttp/src/rh/aead.rs
+++ b/ohttp/src/rh/aead.rs
@@ -121,7 +121,7 @@ impl Aead {
 mod test {
     use super::{
         super::super::{hpke::Aead as AeadId, init},
-        Aead, Mode, SequenceNumber, NONCE_LEN,
+        Aead, Mode, NONCE_LEN, SequenceNumber,
     };
 
     /// Check that the first invocation of encryption matches expected values.
diff --git a/ohttp/src/rh/hpke.rs b/ohttp/src/rh/hpke.rs
index db544f4..156cbb6 100644
--- a/ohttp/src/rh/hpke.rs
+++ b/ohttp/src/rh/hpke.rs
@@ -1,14 +1,15 @@
 use super::SymKey;
 use crate::{
-    hpke::{Aead, Kdf, Kem},
     Error, Res,
+    hpke::{Aead, Kdf, Kem},
 };
 
 use bitcoin_hpke::{
+    Deserializable, OpModeR, OpModeS, Serializable,
     aead::{AeadCtxR, AeadCtxS, AeadTag, ChaCha20Poly1305},
     kdf::HkdfSha256,
     kem::{Kem as KemTrait, SecpK256HkdfSha256},
-    setup_receiver, setup_sender, Deserializable, OpModeR, OpModeS, Serializable,
+    setup_receiver, setup_sender,
 };
 
 use ::rand::thread_rng;
@@ -419,7 +420,7 @@ pub fn derive_key_pair(kem: Kem, ikm: &[u8]) -> Res<(PrivateKey, PublicKey)> {
 
 #[cfg(test)]
 mod test {
-    use super::{generate_key_pair, Config, HpkeR, HpkeS};
+    use super::{Config, HpkeR, HpkeS, generate_key_pair};
     use crate::{
         hpke::{Aead, Kem},
         init,