diff --git a/10/10.3/Dockerfile b/10/10.3/Dockerfile
index eee2cd0..2525f9a 100644
--- a/10/10.3/Dockerfile
+++ b/10/10.3/Dockerfile
@@ -29,23 +29,19 @@ RUN curl -OL https://raw.githubusercontent.com/vishnubob/wait-for-it/master/wait
 # installed into the vendor directory.
 RUN composer config --no-interaction allow-plugins true
 
+# Install Drupal Dev dependencies such as PHPUnit, Behat-Mink, ...
+RUN COMPOSER_MEMORY_LIMIT=-1 composer require --dev drupal/core-dev:~${DRUPAL_VERSION}
+
 # Install Drush.
 # Drush will be heavily use to setup a working Drupal environment.
 RUN COMPOSER_MEMORY_LIMIT=-1 composer require drush/drush:^12.0
 
-# Prepare for Drupal 10.3 upgrade.
-# @see https://www.drupal.org/docs/upgrading-drupal/upgrading-from-drupal-8-to-drupal-9-or-higher
-RUN composer require drupal/core-recommended:~${DRUPAL_VER} --update-with-all-dependencies --no-update
-RUN composer require drupal/core-dev:~${DRUPAL_VER} --dev --update-with-all-dependencies --no-update
-
-# Set the minimum stability to "dev" to allow installing unstable Drupal Core.
-RUN composer config minimum-stability dev
-
-# Perform Drupal 10.1 installation.
-RUN COMPOSER_MEMORY_LIMIT=-1 composer update --with-all-dependencies
-
 # Clean repository.
 RUN apt-get clean && rm -rf /var/lib/apt/lists/*
 
 # Copy a default template for PHPUnit testing.
 COPY templates/phpunit.xml /opt/drupal/web/phpunit.xml
+
+# Create the output directory for PHPUnit.
+RUN mkdir -p /opt/drupal/web/sites/default/files/simpletest/browser_output
+RUN chown www-data:www-data /opt/drupal/web/sites/default/files/simpletest/browser_output
diff --git a/10/10.3/Makefile b/10/10.3/Makefile
index dd63cf9..6461a47 100644
--- a/10/10.3/Makefile
+++ b/10/10.3/Makefile
@@ -1,7 +1,7 @@
 DRUPAL_VER ?= 10.3
 DRUPAL_VER_MAJOR ?= $(shell echo "${DRUPAL_VER}" | grep -oE '^[0-9]+\.[0-9]+')
 
-BASE_IMAGE_TAG = 10.2
+BASE_IMAGE_TAG = 10.3
 ARCH_TO_BUILD ?= "linux/amd64"
 
 REPO = wengerk/drupal-for-contrib
diff --git a/10/10.3/templates/phpunit.xml b/10/10.3/templates/phpunit.xml
index 3318a24..6b39a89 100644
--- a/10/10.3/templates/phpunit.xml
+++ b/10/10.3/templates/phpunit.xml
@@ -22,19 +22,21 @@
     <ini name="memory_limit" value="-1"/>
     <!-- Example SIMPLETEST_BASE_URL value: http://localhost -->
     <env name="SIMPLETEST_BASE_URL" value="http://drupal"/>
-    <!-- Example SIMPLETEST_DB value: mysql://username:password@localhost/databasename#table_prefix -->
+    <!-- Example SIMPLETEST_DB value: mysql://username:password@localhost/database_name#table_prefix -->
     <env name="SIMPLETEST_DB" value="mysql://drupal:drupal@db/drupal"/>
     <!-- Example BROWSERTEST_OUTPUT_DIRECTORY value: /path/to/webroot/sites/simpletest/browser_output -->
     <env name="BROWSERTEST_OUTPUT_DIRECTORY" value="/opt/drupal/web/sites/default/files/simpletest/browser_output"/>
-    <!-- To have browsertest output use an alternative base URL. For example if
-     SIMPLETEST_BASE_URL is an internal DDEV URL, you can set this to the
-     external DDev URL so you can follow the links directly.
-    -->
+    <!-- By default, browser tests will output links that use the base URL set
+     in SIMPLETEST_BASE_URL. However, if your SIMPLETEST_BASE_URL is an internal
+     path (such as may be the case in a virtual or Docker-based environment),
+     you can set the base URL used in the browser test output links to something
+     reachable from your host machine here. This will allow you to follow them
+     directly and view the output. -->
     <env name="BROWSERTEST_OUTPUT_BASE_URL" value=""/>
 
     <!-- Deprecation testing is managed through Symfony's PHPUnit Bridge.
       The environment variable SYMFONY_DEPRECATIONS_HELPER is used to configure
-      the behaviour of the deprecation tests.
+      the behavior of the deprecation tests.
       See https://symfony.com/doc/current/components/phpunit_bridge.html#configuration
       Drupal core's testing framework is setting this variable to its defaults.
       Projects with their own requirements need to manage this variable
@@ -51,13 +53,11 @@
     -->
     <!-- <env name="SYMFONY_DEPRECATIONS_HELPER" value="ignoreFile=.deprecation-ignore.txt"/> -->
 
-    <!-- To disable deprecation testing completely uncomment the next line. -->
-    <!-- <env name="SYMFONY_DEPRECATIONS_HELPER" value="disabled"/> -->
     <!-- Example for changing the driver class for mink tests MINK_DRIVER_CLASS value: 'Drupal\FunctionalJavascriptTests\DrupalSelenium2Driver' -->
     <env name="MINK_DRIVER_CLASS" value=''/>
     <!-- Example for changing the driver args to mink tests MINK_DRIVER_ARGS value: '["http://127.0.0.1:8510"]' -->
     <env name="MINK_DRIVER_ARGS" value=''/>
-    <!-- Example for changing the driver args to webdriver tests MINK_DRIVER_ARGS_WEBDRIVER value: '["chrome", { "chromeOptions": { "w3c": false } }, "http://localhost:4444/wd/hub"]' For using the Firefox browser, replace "chrome" with "firefox" -->
+    <!-- Example for changing the driver args to webdriver tests MINK_DRIVER_ARGS_WEBDRIVER value: '["chrome", { "goog:chromeOptions": { "w3c": false } }, "http://localhost:4444/wd/hub"]' For using the Firefox browser, replace "chrome" with "firefox" -->
     <env name="MINK_DRIVER_ARGS_WEBDRIVER" value='["chrome", {"browserName":"chrome","chromeOptions":{"args":["--disable-gpu","--headless", "--no-sandbox", "--disable-dev-shm-usage"]}}, "http://chrome:9515"]'/>
   </php>
   <testsuites>
@@ -80,39 +80,18 @@
   <listeners>
     <listener class="\Drupal\Tests\Listeners\DrupalListener">
     </listener>
-    <!-- The Symfony deprecation listener has to come after the Drupal listener -->
-    <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener">
-    </listener>
   </listeners>
-  <!-- Filter for coverage reports. -->
-  <filter>
-    <whitelist>
-      <directory>./core/includes</directory>
-      <directory>./core/lib</directory>
-      <directory>./core/modules</directory>
-      <!-- Extensions can have their own test directories, so exclude those. -->
-      <exclude>
-        <directory>./core/modules/*/src/Tests</directory>
-        <directory>./core/modules/*/tests</directory>
-      </exclude>
+  <!-- Settings for coverage reports. -->
+  <coverage>
+    <include>
       <directory>./modules</directory>
-      <exclude>
-        <directory>./modules/*/src/Tests</directory>
-        <directory>./modules/*/tests</directory>
-        <directory>./modules/*/*/src/Tests</directory>
-        <directory>./modules/*/*/tests</directory>
-      </exclude>
-      <directory>./sites</directory>
-      <!-- By definition test classes have no tests. -->
-      <exclude>
-        <directory suffix="Test.php">./</directory>
-        <directory suffix="TestBase.php">./</directory>
-      </exclude>
-    </whitelist>
-  </filter>
-  <!-- Logging for coverage reports. -->
-  <logging>
-    <log type="coverage-clover" target="./build/logs/clover.xml"/>
-    <log type="coverage-html" target="./build/logs/coverage-html"/>
-  </logging>
+    </include>
+    <exclude>
+      <directory>./modules/*/src/Tests</directory>
+      <directory>./modules/*/tests</directory>
+      <directory>./modules/*/*/src/Tests</directory>
+      <directory>./modules/*/*/tests</directory>
+      <directory suffix=".api.php">./modules/**</directory>
+    </exclude>
+  </coverage>
 </phpunit>
diff --git a/10/10.3/tests/config.yaml b/10/10.3/tests/config.yaml
index a3cc79a..5652549 100644
--- a/10/10.3/tests/config.yaml
+++ b/10/10.3/tests/config.yaml
@@ -34,6 +34,12 @@ commandTests:
     command: 'phpunit'
     args: ['--version']
     expectedOutput: ['^PHPUnit 9\.\d\.\d']
+  - name: 'PHPUnit configuration file should works'
+    command: 'phpunit'
+    args: ['-c', '/var/www/html/phpunit.xml', '--group', 'foo']
+    exitCode: 0
+    expectedOutput: [ 'No tests executed!' ]
+    excludedOutput: [ 'is not a writable directory.' ]
 fileExistenceTests:
   - name: 'Root'
     path: '/'
@@ -62,3 +68,9 @@ fileExistenceTests:
     permissions: 'drwxr-xr-x'
     uid: 33
     gid: 33
+  - name: 'Drupal PHPUnit Output'
+    path: '/opt/drupal/web/sites/default/files/simpletest/browser_output'
+    shouldExist: true
+    permissions: 'drwxr-xr-x'
+    uid: 33
+    gid: 33
diff --git a/README.md b/README.md
index 58da437..0a0195d 100644
--- a/README.md
+++ b/README.md
@@ -27,17 +27,17 @@ Overview:
 | `11.1` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/11/11.1/Dockerfile) | 11.x-dev |
 | `11.0` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/11/11.0/Dockerfile) | 11.0.x   |
 | `10.4` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.4/Dockerfile) | 10.4-dev |
-| `10.3` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.3/Dockerfile) | 10.3-dev |
-| `10.2` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.2/Dockerfile) | 10.2.0+  |
-| `10.1` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.1/Dockerfile) | 10.1.0+  |
-| `10.0` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.0/Dockerfile) | 10.0.0+  |
-| `9.5` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.5/Dockerfile)    | 9.5.0+   |
-| `9.4` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.4/Dockerfile)    | 9.4.0+   |
-| `9.3` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.3/Dockerfile)    | 9.3.0+   |
-| `9.2` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.2/Dockerfile)    | 9.2.0+   |
-| `9.1` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.1/Dockerfile)    | 9.1.0+   |
-| `9.0` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.0/Dockerfile)    | 9.0.10+  |
-| `8.9` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/8/8.9/Dockerfile)    | 8.9.11+  |
+| `10.3` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.3/Dockerfile) | 10.3.x   |
+| `10.2` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.2/Dockerfile) | 10.2.x   |
+| `10.1` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.1/Dockerfile) | 10.1.x   |
+| `10.0` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/10/10.0/Dockerfile) | 10.0.x   |
+| `9.5` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.5/Dockerfile)    | 9.5.x    |
+| `9.4` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.4/Dockerfile)    | 9.4.x    |
+| `9.3` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.3/Dockerfile)    | 9.3.x    |
+| `9.2` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.2/Dockerfile)    | 9.2.x    |
+| `9.1` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.1/Dockerfile)    | 9.1.x    |
+| `9.0` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/9/9.0/Dockerfile)    | 9.0.x    |
+| `8.9` [_(Dockerfile)_](https://github.com/wengerk/docker-drupal-for-contrib/tree/master/8/8.9/Dockerfile)    | 8.9.x    |
 
 ## Usage in a Drupal Contribution Modules/Themes