diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 30c035bd4..f09ed0fe2 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -89,7 +89,7 @@ jobs:
         uses: "shivammathur/setup-php@v2"
         with:
           coverage: "none"
-          extensions: "intl"
+          extensions: "intl, zip"
           ini-values: "memory_limit=-1, phar.readonly=0"
           php-version: "${{ matrix.php-version }}"
 
diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
index 87cd149eb..d2894e09b 100644
--- a/.github/workflows/phpstan.yml
+++ b/.github/workflows/phpstan.yml
@@ -31,7 +31,7 @@ jobs:
         uses: "shivammathur/setup-php@v2"
         with:
           coverage: "none"
-          extensions: "intl"
+          extensions: "intl, zip"
           ini-values: "memory_limit=-1"
           php-version: "${{ matrix.php-version }}"
           tools: "cs2pr"
@@ -52,5 +52,5 @@ jobs:
 
       - name: Run PHPStan
         run: |
-          bin/composer require --dev phpstan/phpstan:^0.12 phpunit/phpunit:^7.5 --with-all-dependencies
+          bin/composer require --dev phpstan/phpstan:^0.12.26 phpunit/phpunit:^7.5 --with-all-dependencies
           vendor/bin/phpstan analyse --configuration=phpstan/config.neon || vendor/bin/phpstan analyse --configuration=phpstan/config.neon --error-format=checkstyle | cs2pr
diff --git a/phpstan/config.neon b/phpstan/config.neon
index d9bf7f8c6..c8c130a31 100644
--- a/phpstan/config.neon
+++ b/phpstan/config.neon
@@ -1,7 +1,5 @@
 parameters:
     level: 1
-    autoload_files:
-        - '../src/bootstrap.php'
     excludes_analyse:
        - '../tests/Composer/Test/Fixtures/*'
        - '../tests/Composer/Test/Autoload/Fixtures/*'
@@ -27,6 +25,10 @@ parameters:
 
         # BC with older PHPUnit
         - '~^Call to an undefined static method PHPUnit\\Framework\\TestCase::setExpectedException\(\)\.$~'
+
+        # ZipArchive::* Class constants are already checked before use.
+        - '~^Access to undefined constant ZipArchive::~'
+
     paths:
         - ../src
         - ../tests