diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 14a154a..d2469e1 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -8,14 +8,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rust: [1.56.0, stable, beta, nightly]
+        rust: [1.71.0, stable, beta, nightly]
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        if: startsWith(matrix.rust, '1')
-        with:
-          path: ~/.cargo/registry/index
-          key: cargo-${{ matrix.rust }}-git-index
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
@@ -39,7 +34,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.70.0
+      - uses: dtolnay/rust-toolchain@1.71.0
         with:
           components: rustfmt
       - run: cargo fmt --all --check
diff --git a/.github/workflows/main.yaml b/.github/workflows/main.yaml
index e181a3d..ac37353 100644
--- a/.github/workflows/main.yaml
+++ b/.github/workflows/main.yaml
@@ -13,14 +13,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rust: [1.56.0, stable]
+        rust: [1.71.0, stable]
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        if: startsWith(matrix.rust, '1')
-        with:
-          path: ~/.cargo/registry/index
-          key: cargo-${{ matrix.rust }}-git-index
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
diff --git a/.github/workflows/pr.yaml b/.github/workflows/pr.yaml
index 1cadac0..a7af211 100644
--- a/.github/workflows/pr.yaml
+++ b/.github/workflows/pr.yaml
@@ -9,14 +9,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rust: [1.56.0, stable]
+        rust: [1.71.0, stable]
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        if: startsWith(matrix.rust, '1')
-        with:
-          path: ~/.cargo/registry/index
-          key: cargo-${{ matrix.rust }}-git-index
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
diff --git a/Cargo.toml b/Cargo.toml
index 4a13a07..532017f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,16 +8,16 @@ categories = [ "science" ]
 license = "MIT OR Apache-2.0"
 name = "num-derive"
 repository = "https://github.com/rust-num/num-derive"
-version = "0.4.2"
+version = "0.5.0"
 readme = "README.md"
 exclude = ["/ci/*", "/.github/*"]
 edition = "2021"
-rust-version = "1.56.0"
+rust-version = "1.71.0"
 
 [dependencies]
 proc-macro2 = "1"
 quote = "1"
-syn = "2.0.5"
+syn = "3"
 
 [dev-dependencies]
 num = "0.4"
diff --git a/README.md b/README.md
index 302b0d0..b36c8ce 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 [![crate](https://img.shields.io/crates/v/num-derive.svg)](https://crates.io/crates/num-derive)
 [![documentation](https://docs.rs/num-derive/badge.svg)](https://docs.rs/num-derive)
-[![minimum rustc 1.56](https://img.shields.io/badge/rustc-1.56+-red.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
+[![minimum rustc 1.71](https://img.shields.io/badge/rustc-1.71+-red.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
 [![build status](https://github.com/rust-num/num-derive/actions/workflows/main.yaml/badge.svg)](https://github.com/rust-num/num-derive/actions/workflows/main.yaml)
 
 Procedural macros to derive numeric traits in Rust.
@@ -14,7 +14,7 @@ Add this to your `Cargo.toml`:
 ```toml
 [dependencies]
 num-traits = "0.2"
-num-derive = "0.4"
+num-derive = "0.5"
 ```
 
 and this to your crate root:
@@ -51,7 +51,7 @@ Release notes are available in [RELEASES.md](RELEASES.md).
 
 ## Compatibility
 
-The `num-derive` crate is tested for rustc 1.56 and greater.
+The `num-derive` crate is tested for rustc 1.71 and greater.
 
 ## License
 
diff --git a/RELEASES.md b/RELEASES.md
index bbf6d53..dead040 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -1,3 +1,10 @@
+# Release 0.5.0 (2026-07-20)
+
+- [Upgrade to `syn v3`.][71]
+  - This raises the minimum supported rustc to 1.71.
+
+[71]: https://github.com/rust-num/num-derive/pull/71
+
 # Release 0.4.2 (2024-02-06)
 
 - [Use anon-const to avoid RFC 3373 warnings.][62]
diff --git a/ci/check/Cargo.toml b/ci/check/Cargo.toml
index 573bbc9..3404b22 100644
--- a/ci/check/Cargo.toml
+++ b/ci/check/Cargo.toml
@@ -1,9 +1,9 @@
 [package]
 name = "check"
 version = "0.1.0"
-authors = ["Josh Stone <cuviper@gmail.com>"]
 edition = "2018"
-rust-version = "1.56.0"
+rust-version = "1.71.0"
+publish = false
 
 [dependencies.num-derive]
 path = "../.."
diff --git a/ci/import/Cargo.toml b/ci/import/Cargo.toml
index 303d1d0..3aebf5c 100644
--- a/ci/import/Cargo.toml
+++ b/ci/import/Cargo.toml
@@ -1,10 +1,9 @@
 [package]
 name = "import"
 version = "0.0.1"
-authors = ["jean-airoldie <25088801+jean-airoldie@users.noreply.github.com>"]
 edition = "2018"
+rust-version = "1.71.0"
 publish = false
-rust-version = "1.56.0"
 
 [dependencies]
 num-derive = { path = "../.." }
diff --git a/ci/rustup.sh b/ci/rustup.sh
index 5289138..461e552 100755
--- a/ci/rustup.sh
+++ b/ci/rustup.sh
@@ -5,6 +5,6 @@
 set -ex
 
 ci=$(dirname $0)
-for version in 1.56.0 stable beta nightly; do
+for version in 1.71.0 stable beta nightly; do
     rustup run "$version" "$ci/test_full.sh"
 done
diff --git a/ci/test_full.sh b/ci/test_full.sh
index ddbafcf..903ff80 100755
--- a/ci/test_full.sh
+++ b/ci/test_full.sh
@@ -3,7 +3,7 @@
 set -e
 
 CRATE=num-derive
-MSRV=1.56
+MSRV=1.71
 
 get_rust_version() {
   local array=($(rustc --version));
diff --git a/src/lib.rs b/src/lib.rs
index 207602b..49750c6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_type = "proc-macro"]
-#![doc(html_root_url = "https://docs.rs/num-derive/0.3")]
 #![recursion_limit = "512"]
 
 //! Procedural macros to derive numeric traits in Rust.
@@ -21,7 +20,7 @@
 //! ```toml
 //! [dependencies]
 //! num-traits = "0.2"
-//! num-derive = "0.3"
+//! num-derive = "0.5"
 //! ```
 //!
 //! Then you can derive traits on your own types: