diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index be3d46e..92055ee 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,8 +11,8 @@ jobs:
     strategy:
       matrix:
         os:
-          - ubuntu-20.04
-          - windows-2019
+          - ubuntu-22.04
+          - windows-2022
         php:
           - 8.2
           - 8.1
@@ -27,11 +27,12 @@ jobs:
           - 5.4
           - 5.3
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
           coverage: xdebug
+          ini-file: development
       - run: composer install
       - run: vendor/bin/phpunit --coverage-text
         if: ${{ matrix.php >= 7.3 }}
@@ -41,14 +42,20 @@ jobs:
 
   PHPUnit-hhvm:
     name: PHPUnit (HHVM)
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-22.04
     continue-on-error: true
     steps:
-      - uses: actions/checkout@v2
-      - uses: azjezz/setup-hhvm@v1
+      - uses: actions/checkout@v3
+      - run: cp "$(which composer)" composer.phar && ./composer.phar self-update --2.2 # downgrade Composer for HHVM
+      - name: Run hhvm composer.phar install
+        uses: docker://hhvm/hhvm:3.30-lts-latest
         with:
-          version: lts-3.30
-      - run: composer self-update --2.2 # downgrade Composer for HHVM
-      - run: hhvm $(which composer) install
-      - run: hhvm vendor/bin/phpunit
-      - run: hhvm examples/13-benchmark-throughput.php
+          args: hhvm composer.phar install
+      - name: Run hhvm vendor/bin/phpunit
+        uses: docker://hhvm/hhvm:3.30-lts-latest
+        with:
+          args: hhvm vendor/bin/phpunit
+      - name: Run hhvm examples/13-benchmark-throughput.php
+        uses: docker://hhvm/hhvm:3.30-lts-latest
+        with:
+          args: hhvm examples/13-benchmark-throughput.php
diff --git a/composer.json b/composer.json
index 32aa713..5750aff 100644
--- a/composer.json
+++ b/composer.json
@@ -32,14 +32,18 @@
         "react/stream": "^1.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.3 || ^5.7 || ^4.8.35",
+        "phpunit/phpunit": "^9.5 || ^5.7 || ^4.8.35",
         "react/socket": "^1.8",
         "sebastian/environment": "^5.0 || ^3.0 || ^2.0 || ^1.0"
     },
     "autoload": {
-        "psr-4": { "React\\ChildProcess\\": "src" }
+        "psr-4": {
+            "React\\ChildProcess\\": "src/"
+        }
     },
     "autoload-dev": {
-        "psr-4": { "React\\Tests\\ChildProcess\\": "tests" }
+        "psr-4": {
+            "React\\Tests\\ChildProcess\\": "tests/"
+        }
     }
 }
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index fa88e7e..7a9577e 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,11 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<!-- PHPUnit configuration file with new format for PHPUnit 9.3+ -->
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+<!-- PHPUnit configuration file with new format for PHPUnit 9.5+ -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
          bootstrap="vendor/autoload.php"
+         cacheResult="false"
          colors="true"
-         cacheResult="false">
+         convertDeprecationsToExceptions="true">
     <testsuites>
         <testsuite name="React Test Suite">
             <directory>./tests/</directory>
@@ -16,4 +17,12 @@
             <directory>./src/</directory>
         </include>
     </coverage>
+    <php>
+        <ini name="error_reporting" value="-1" />
+        <!-- Evaluate assertions, requires running with "php -d zend.assertions=1 vendor/bin/phpunit" -->
+        <!-- <ini name="zend.assertions=1" value="1" /> -->
+        <ini name="assert.active" value="1" />
+        <ini name="assert.exception" value="1" />
+        <ini name="assert.bail" value="0" />
+    </php>
 </phpunit>
diff --git a/phpunit.xml.legacy b/phpunit.xml.legacy
index d515789..ac5600a 100644
--- a/phpunit.xml.legacy
+++ b/phpunit.xml.legacy
@@ -1,15 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<!-- PHPUnit configuration file with old format for PHPUnit 9.2 or older -->
+<!-- PHPUnit configuration file with old format for legacy PHPUnit -->
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/4.8/phpunit.xsd"
          bootstrap="vendor/autoload.php"
-         colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         processIsolation="false"
-         stopOnFailure="false">
+         colors="true">
     <testsuites>
         <testsuite name="React Test Suite">
             <directory>./tests/</directory>
@@ -20,4 +15,12 @@
             <directory>./src/</directory>
         </whitelist>
     </filter>
+    <php>
+        <ini name="error_reporting" value="-1" />
+        <!-- Evaluate assertions, requires running with "php -d zend.assertions=1 vendor/bin/phpunit" -->
+        <!-- <ini name="zend.assertions=1" value="1" /> -->
+        <ini name="assert.active" value="1" />
+        <ini name="assert.exception" value="1" />
+        <ini name="assert.bail" value="0" />
+    </php>
 </phpunit>