diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index e8232d8..f8b244b 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: dtolnay/rust-toolchain@stable
     - name: Run Tests
       run: cargo test
@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: dtolnay/rust-toolchain@nightly
     - name: Run Tests
       run: cargo test
@@ -40,7 +40,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: dtolnay/rust-toolchain@nightly
       with:
         components: clippy
@@ -50,7 +50,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: dtolnay/rust-toolchain@nightly
     - name: Check docs
       run: RUSTDOCFLAGS="-D warnings" cargo doc --no-deps
@@ -58,7 +58,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: dtolnay/rust-toolchain@stable
       with:
         components: rustfmt
@@ -72,7 +72,7 @@ jobs:
       matrix:
         sanitizer: [address] # TODO: enable thread, memory, leak.
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: dtolnay/rust-toolchain@nightly
       with:
         components: rust-src