diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e74c5c042..e57db134b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -45,7 +45,7 @@ jobs:
     strategy:
       matrix:
         target:
-          - wasm32-wasi
+          - wasm32-wasip1
           - thumbv7em-none-eabihf
     steps:
       - uses: actions/checkout@v4
@@ -70,9 +70,9 @@ jobs:
       - name: Add lazy_static with the spin_no_std feature
         working-directory: ./ci-build
         run: cargo add lazy_static --no-default-features --features "spin_no_std"
-      - name: Add typenum with the no_std feature
+      - name: Add typenum with no default features
         working-directory: ./ci-build
-        run: cargo add typenum --no-default-features --features "no_std"
+        run: cargo add typenum --no-default-features
       - name: Show Cargo.toml for the synthetic crate
         working-directory: ./ci-build
         run: cat Cargo.toml
diff --git a/.github/workflows/lints-stable.yml b/.github/workflows/lints-stable.yml
index 10ff2eb34..c159d8f59 100644
--- a/.github/workflows/lints-stable.yml
+++ b/.github/workflows/lints-stable.yml
@@ -23,7 +23,7 @@ jobs:
     strategy:
       matrix:
         target:
-          - wasm32-wasi
+          - wasm32-wasip1
     steps:
       - uses: actions/checkout@v4
         with:
@@ -47,9 +47,9 @@ jobs:
       - name: Add lazy_static with the spin_no_std feature
         working-directory: ./ci-build
         run: cargo add lazy_static --no-default-features --features "spin_no_std"
-      - name: Add typenum with the no_std feature
+      - name: Add typenum with no default features
         working-directory: ./ci-build
-        run: cargo add typenum --no-default-features --features "no_std"
+        run: cargo add typenum --no-default-features
       - name: Show Cargo.toml for the synthetic crate
         working-directory: ./ci-build
         run: cat Cargo.toml
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 96126a262..128dd63dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ and this project adheres to Rust's notion of
 ## [Unreleased]
 
 ### Changed
+- MSRV is now 1.85.1
+- Migrated from yanked `core2` library to `corez`
 - `orchard::pczt::Bundle::extract` now takes its `self` argument by
   reference instead of by value.
 
diff --git a/Cargo.lock b/Cargo.lock
index f63644de0..4a9a14680 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -422,13 +422,10 @@ dependencies = [
 ]
 
 [[package]]
-name = "core2"
-version = "0.3.3"
+name = "corez"
+version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "239fa3ae9b63c2dc74bd3fa852d4792b8b305ae64eeede946265b6af62f1fff3"
-dependencies = [
- "memchr",
-]
+checksum = "4df6f98652d30167eaeea34d77b730e07c8caba6df17bd4551842b9b8da01deb"
 
 [[package]]
 name = "cpp_demangle"
@@ -1443,7 +1440,7 @@ dependencies = [
  "aes",
  "bitvec",
  "blake2b_simd",
- "core2",
+ "corez",
  "criterion",
  "ff",
  "fpe",
diff --git a/Cargo.toml b/Cargo.toml
index 368e0c9a5..eed13e471 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,7 @@ authors = [
     "Kris Nuttycombe <kris@electriccoin.co>",
 ]
 edition = "2021"
-rust-version = "1.70"
+rust-version = "1.85.1"
 description = "The Orchard shielded transaction protocol"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/zcash/orchard"
@@ -60,7 +60,7 @@ getset = "0.1"
 tracing = { version = "0.1", default-features = false }
 
 # No-std support
-core2 = { version = "0.3", default-features = false, features = ["alloc"] }
+corez = { version = "0.1.1", default-features = false, features = ["alloc"] }
 
 # Developer tooling dependencies
 image = { version = "0.24", optional = true }
@@ -84,7 +84,7 @@ bench = false
 
 [features]
 default = ["circuit", "multicore", "std"]
-std = ["core2/std", "group/wnaf-memuse", "reddsa/std"]
+std = ["corez/std", "group/wnaf-memuse", "reddsa/std"]
 circuit = ["dep:halo2_gadgets", "dep:halo2_proofs", "std"]
 unstable-frost = []
 multicore = ["halo2_proofs?/multicore"]
diff --git a/README.md b/README.md
index 8fdcd2730..1e0aab030 100644
--- a/README.md
+++ b/README.md
@@ -10,13 +10,9 @@ Requires Rust 1.70+.
 ## `no_std` compatibility
 
 In order to take advantage of `no_std` builds, downstream users of this crate
-must enable:
-
-* the `spin_no_std` feature of the `lazy_static` crate; and
-* the `no_std` feature of the `typenum` crate.
-
-This is needed because the `--no-default-features` builds of these crates still
-rely on `std`.
+must enable the `spin_no_std` feature of the `lazy_static` crate. This is
+needed because the `--no-default-features` build of `lazy_static` still relies
+on `std`.
 
 ## License
 
diff --git a/benches/utils.rs b/benches/utils/mod.rs
similarity index 100%
rename from benches/utils.rs
rename to benches/utils/mod.rs
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index cad9254a9..0542ef5eb 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.70.0"
+channel = "1.85.1"
 components = [ "clippy", "rustfmt" ]
diff --git a/src/constants/fixed_bases.rs b/src/constants/fixed_bases.rs
index 14b7913ad..de41e4a8f 100644
--- a/src/constants/fixed_bases.rs
+++ b/src/constants/fixed_bases.rs
@@ -53,12 +53,10 @@ pub const FIXED_BASE_WINDOW_SIZE: usize = 3;
 pub const H: usize = 1 << FIXED_BASE_WINDOW_SIZE;
 
 /// Number of windows for a full-width scalar
-pub const NUM_WINDOWS: usize =
-    (L_ORCHARD_SCALAR + FIXED_BASE_WINDOW_SIZE - 1) / FIXED_BASE_WINDOW_SIZE;
+pub const NUM_WINDOWS: usize = L_ORCHARD_SCALAR.div_ceil(FIXED_BASE_WINDOW_SIZE);
 
 /// Number of windows for a short signed scalar
-pub const NUM_WINDOWS_SHORT: usize =
-    (L_VALUE + FIXED_BASE_WINDOW_SIZE - 1) / FIXED_BASE_WINDOW_SIZE;
+pub const NUM_WINDOWS_SHORT: usize = L_VALUE.div_ceil(FIXED_BASE_WINDOW_SIZE);
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 // A sum type for both full-width and short bases. This enables us to use the
diff --git a/src/issuance.rs b/src/issuance.rs
index a87a77836..f7983249b 100644
--- a/src/issuance.rs
+++ b/src/issuance.rs
@@ -1534,14 +1534,14 @@ mod tests {
         );
     }
 
-    #[test]
-    fn issue_bundle_verify_fail_bad_signature() {
-        impl IssueBundle<Signed> {
-            pub fn set_authorization(&mut self, authorization: Signed) {
-                self.authorization = authorization;
-            }
+    impl IssueBundle<Signed> {
+        pub(crate) fn set_authorization(&mut self, authorization: Signed) {
+            self.authorization = authorization;
         }
+    }
 
+    #[test]
+    fn issue_bundle_verify_fail_bad_signature() {
         let params = setup_params();
         let mut rng = OsRng;
         let (mut signed, _) = new_signed_bundle(&params, b"bad sig", 5);
diff --git a/src/keys.rs b/src/keys.rs
index 9a2f24c77..0236620c4 100644
--- a/src/keys.rs
+++ b/src/keys.rs
@@ -1,7 +1,7 @@
 //! Key structures for Orchard.
 
 use alloc::vec::Vec;
-use core2::io::{self, Read, Write};
+use corez::io::{self, Read, Write};
 
 use ::zip32::ChildIndex;
 use aes::Aes256;
diff --git a/src/note/asset_base.rs b/src/note/asset_base.rs
index 0e41d2778..602cced94 100644
--- a/src/note/asset_base.rs
+++ b/src/note/asset_base.rs
@@ -177,7 +177,7 @@ impl AssetBase {
 impl Hash for AssetBase {
     fn hash<H: Hasher>(&self, h: &mut H) {
         h.write(&self.to_bytes());
-        h.finish();
+        let _ = h.finish();
     }
 }
 
diff --git a/tests/zsa.rs b/tests/zsa.rs
index 57cccb786..c3da73ecb 100644
--- a/tests/zsa.rs
+++ b/tests/zsa.rs
@@ -353,7 +353,7 @@ fn zsa_issue_and_transfer() {
 
     let zsa_spend1_asset1 = TestSpendInfo {
         note: zsa_note1_asset1,
-        merkle_path: merkle_paths.get(0).unwrap().clone(),
+        merkle_path: merkle_paths.first().unwrap().clone(),
     };
     let zsa_spend2_asset1 = TestSpendInfo {
         note: zsa_note2_asset1,