diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a6a86c879..ea52811c7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -12,7 +12,13 @@ jobs:
   build:
     name: "Build"
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-20.04
+            php-version: 7.4
 
     steps:
       - name: "Checkout"
@@ -32,7 +38,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 7.4
+          php-version: ${{ matrix.php-version }}
           extensions: mbstring, xml, ctype, iconv
           ini-values: phar.readonly=0
           coverage: none
@@ -72,11 +78,15 @@ jobs:
 
     needs: build
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
 
     strategy:
       matrix:
-        php-version: [ 7.2, 8.0 ]
+        include:
+          - os: ubuntu-18.04
+            php-version: 7.2
+          - os: ubuntu-20.04
+            php-version: 8.0
 
     steps:
       - name: "Checkout"
diff --git a/.github/workflows/static-analysis.yml b/.github/workflows/static-analysis.yml
index 77fe7585c..eaf76e74c 100644
--- a/.github/workflows/static-analysis.yml
+++ b/.github/workflows/static-analysis.yml
@@ -12,7 +12,13 @@ jobs:
   coding-standards:
     name: "Coding Standards"
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-18.04
+            php-version: 7.2
 
     steps:
       - name: "Checkout"
@@ -32,7 +38,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 7.2
+          php-version: ${{ matrix.php-version }}
           extensions: mbstring, xml, ctype, iconv
           coverage: none
           tools: phive
@@ -46,7 +52,13 @@ jobs:
   static-code-analysis-phpstan:
     name: "Static Code Analysis by PHPStan"
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-18.04
+            php-version: 7.2
 
     steps:
       - name: "Checkout"
@@ -66,7 +78,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 7.2
+          php-version: ${{ matrix.php-version }}
           extensions: mbstring, xml, ctype, iconv
           coverage: none
           tools: phive, composer:v2
@@ -97,7 +109,13 @@ jobs:
   static-code-analysis-psalm:
     name: "Static Code Analysis by Psalm"
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-20.04
+            php-version: 7.4
 
     steps:
       - name: "Checkout"
@@ -117,7 +135,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 7.4
+          php-version: ${{ matrix.php-version }}
           extensions: mbstring, xml, ctype, iconv
           coverage: none
           tools: phive, composer:v2
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 297b3eaa3..29b922273 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -10,13 +10,17 @@ name: "Tests"
 
 jobs:
   unit-tests:
-    name: "PHP ${{ matrix.php-version }} Test"
-
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
 
     strategy:
       matrix:
-        php-version: [7.2, 7.3, 7.4, 8.0]
+        os: [ubuntu-20.04]
+        php-version: [7.4, 8.0]
+        include:
+          - os: ubuntu-18.04
+            php-version: 7.2
+          - os: ubuntu-18.04
+            php-version: 7.3
 
     steps:
       - name: "Checkout"
@@ -62,13 +66,13 @@ jobs:
         run: make tests
 
   infection:
-    name: "PHP ${{ matrix.php-version }} Infection"
-
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
 
     strategy:
       matrix:
-        php-version: [ 7.4 ]
+        include:
+          - os: ubuntu-20.04
+            php-version: 7.4
 
     steps:
       - name: "Checkout"