diff --git a/.github/workflows/.env b/.github/workflows/.env
new file mode 100644
index 00000000..1c834f50
--- /dev/null
+++ b/.github/workflows/.env
@@ -0,0 +1,2 @@
+MSRV=1.75.0
+UBUNTU_VERSION=ubuntu-22.04
diff --git a/.github/workflows/changelog.yml b/.github/workflows/changelog.yml
index 04737aa8..99731a39 100644
--- a/.github/workflows/changelog.yml
+++ b/.github/workflows/changelog.yml
@@ -5,9 +5,9 @@ on:
 
 jobs:
   test:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - run: bash -c "! git diff --exit-code origin/master... CHANGELOG.md"
diff --git a/.github/workflows/esprc.yml b/.github/workflows/esprc.yml
index 0d18749e..bfa69ad2 100644
--- a/.github/workflows/esprc.yml
+++ b/.github/workflows/esprc.yml
@@ -8,17 +8,17 @@ on:
 
 jobs:
   parse:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     strategy:
       matrix:
         ap:
           - "201"
           - "203"
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
     - uses: actions-rs/toolchain@v1
       with:
-        toolchain: ${{ vars.MSRV }}
+        toolchain: ${{ env.MSRV }}
         profile: minimal
         default: true
         override: true
@@ -28,17 +28,17 @@ jobs:
         args: --release --bin esprc -- ./schemas/APs/10303-${{ matrix.ap }}-aim-long.exp --check
 
   generate:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     strategy:
       matrix:
         ap:
           - "201"
           - "203"
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
     - uses: actions-rs/toolchain@v1
       with:
-        toolchain: ${{ vars.MSRV }}
+        toolchain: ${{ env.MSRV }}
         profile: minimal
         components: rustfmt
         default: true
diff --git a/.github/workflows/gh-pages.yml b/.github/workflows/gh-pages.yml
index afce9694..c3bdf631 100644
--- a/.github/workflows/gh-pages.yml
+++ b/.github/workflows/gh-pages.yml
@@ -7,12 +7,12 @@ on:
 
 jobs:
   pages:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - uses: actions-rs/toolchain@v1
       with:
-        toolchain: ${{ vars.MSRV }}
+        toolchain: ${{ env.MSRV }}
         profile: minimal
         default: true
         override: true
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 6962fe99..c59ff9e4 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -8,14 +8,14 @@ on:
 
 jobs:
   test:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     strategy:
       matrix:
         rust:
           - stable
-          - ${{ vars.MSRV }}
+          - ${{ env.MSRV }}
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
     - uses: actions-rs/toolchain@v1
       with:
         profile: minimal
@@ -30,12 +30,12 @@ jobs:
         args: --all-features
 
   check-format:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
     - uses: actions-rs/toolchain@v1
       with:
-        toolchain: ${{ vars.MSRV }}
+        toolchain: ${{ env.MSRV }}
         profile: minimal
         components: rustfmt
         default: true
@@ -46,12 +46,12 @@ jobs:
         args: -- --check
 
   doc:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
     - uses: actions-rs/toolchain@v1
       with:
-        toolchain: ${{ vars.MSRV }}
+        toolchain: ${{ env.MSRV }}
         profile: minimal
         default: true
         override: true
@@ -61,12 +61,12 @@ jobs:
         args: --no-deps
 
   clippy:
-    runs-on: ${{ vars.UBUNTU_VERSION }}
+    runs-on: ${{ env.UBUNTU_VERSION }}
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
     - uses: actions-rs/toolchain@v1
       with:
-        toolchain: ${{ vars.MSRV }}
+        toolchain: ${{ env.MSRV }}
         profile: minimal
         components: clippy
         default: true
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 50a3f6b4..d2c85aee 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,11 @@ In addition to original Keep-a-Changelog, we use following rules:
   - This will be checked by GitHub Actions
 - Each Pull Request MAY correspond to one or more lines in this file
 
+## Unreleased
+
+### Internal
+- Using `.env` variables for Actions.
+
 ## 0.4.0 - 2024-09-20
 
 ### Added