diff --git a/.github/workflows/code-standards.yml b/.github/workflows/code-standards.yml
index e507895..4b5566d 100644
--- a/.github/workflows/code-standards.yml
+++ b/.github/workflows/code-standards.yml
@@ -29,7 +29,8 @@ on:
             "whitespace_after_comma_in_array": true,
             "no_whitespace_in_blank_line": true,
             "binary_operator_spaces": {"default": "at_least_single_space"},
-            "no_extra_blank_lines": true
+            "no_extra_blank_lines": true,
+            "nullable_type_declaration_for_default_null_value": true
           }
       add-rules:
         type: string
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 032f87f..026c958 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -11,7 +11,7 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ ubuntu-latest ]
-                php: [ "8.0", "8.1", "8.2", "8.3" ]
+                php: [ "8.0", "8.1", "8.2", "8.3", "8.4" ]
         name: PHP ${{matrix.php }} Unit Test
         steps:
             - uses: actions/checkout@v4
diff --git a/examples/class_vars.legacy.php b/examples/class_vars.legacy.php
index 286bc76..b775830 100644
--- a/examples/class_vars.legacy.php
+++ b/examples/class_vars.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\ClassVars;
 
 // new client surface doesn't exist (yet)
 use Google\ApiCore\LongRunning\OperationsClient;
diff --git a/examples/class_vars.new.php b/examples/class_vars.new.php
index 628fb07..056ae09 100644
--- a/examples/class_vars.new.php
+++ b/examples/class_vars.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\ClassVars;
 
 // new client surface doesn't exist (yet)
 use Google\ApiCore\LongRunning\OperationsClient;
diff --git a/examples/kitchen_sink.legacy.php b/examples/kitchen_sink.legacy.php
index 936401a..0a98fbd 100644
--- a/examples/kitchen_sink.legacy.php
+++ b/examples/kitchen_sink.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\KitchenSink;
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
 use Google\Cloud\Dlp\V2\InspectConfig;
diff --git a/examples/kitchen_sink.new.php b/examples/kitchen_sink.new.php
index 5be74ac..6962b0b 100644
--- a/examples/kitchen_sink.new.php
+++ b/examples/kitchen_sink.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\KitchenSink;
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
 use Google\Cloud\Dlp\V2\CreateDlpJobRequest;
diff --git a/examples/mixins.legacy.php b/examples/mixins.legacy.php
index 6382620..abfa445 100644
--- a/examples/mixins.legacy.php
+++ b/examples/mixins.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\Mixins;
 
 use Google\Cloud\SecretManager\V1\SecretManagerServiceClient;
 use Google\Cloud\Iam\V1\Binding;
diff --git a/examples/mixins.new.php b/examples/mixins.new.php
index 4b0348f..6d17d82 100644
--- a/examples/mixins.new.php
+++ b/examples/mixins.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\Mixins;
 
 use Google\Cloud\Iam\V1\Binding;
 use Google\Cloud\Iam\V1\GetIamPolicyRequest;
diff --git a/examples/multiple_clients.legacy.php b/examples/multiple_clients.legacy.php
index 8fe44f8..4042018 100644
--- a/examples/multiple_clients.legacy.php
+++ b/examples/multiple_clients.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\MultipleClients;
 
 // new client surface doesn't exist (yet)
 use Google\ApiCore\LongRunning\OperationsClient;
diff --git a/examples/multiple_clients.new.php b/examples/multiple_clients.new.php
index f87b65a..65de2c6 100644
--- a/examples/multiple_clients.new.php
+++ b/examples/multiple_clients.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\MultipleClients;
 
 // new client surface doesn't exist (yet)
 use Google\ApiCore\LongRunning\OperationsClient;
diff --git a/examples/no_args.legacy.php b/examples/no_args.legacy.php
index 4b45383..9a352a5 100644
--- a/examples/no_args.legacy.php
+++ b/examples/no_args.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\NoArgs;
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
 
diff --git a/examples/no_args.new.php b/examples/no_args.new.php
index 021bafb..82cfe97 100644
--- a/examples/no_args.new.php
+++ b/examples/no_args.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\NoArgs;
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
 use Google\Cloud\Dlp\V2\ListInfoTypesRequest;
diff --git a/examples/non_rpc_methods.legacy.php b/examples/non_rpc_methods.legacy.php
index 07f8a76..32f6080 100644
--- a/examples/non_rpc_methods.legacy.php
+++ b/examples/non_rpc_methods.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\NonRpcMethods;
 
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
diff --git a/examples/non_rpc_methods.new.php b/examples/non_rpc_methods.new.php
index 72e37bf..80db511 100644
--- a/examples/non_rpc_methods.new.php
+++ b/examples/non_rpc_methods.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\NonRpcMethods;
 
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
diff --git a/examples/optional_args.legacy.php b/examples/optional_args.legacy.php
index a6d3a44..2f10295 100644
--- a/examples/optional_args.legacy.php
+++ b/examples/optional_args.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\OptionalArgs;
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
 use Google\Cloud\Dlp\V2\InspectConfig;
diff --git a/examples/optional_args.new.php b/examples/optional_args.new.php
index d666599..9b325d5 100644
--- a/examples/optional_args.new.php
+++ b/examples/optional_args.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\OptionalArgs;
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
 use Google\Cloud\Dlp\V2\CreateDlpJobRequest;
diff --git a/examples/optional_args_array_keyword.legacy.php b/examples/optional_args_array_keyword.legacy.php
index 0178bc4..ae18c45 100644
--- a/examples/optional_args_array_keyword.legacy.php
+++ b/examples/optional_args_array_keyword.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\OptionalArgsArrayKeyword;
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
 use Google\Cloud\Dlp\V2\InspectConfig;
diff --git a/examples/optional_args_array_keyword.new.php b/examples/optional_args_array_keyword.new.php
index 9ea8f2f..001f334 100644
--- a/examples/optional_args_array_keyword.new.php
+++ b/examples/optional_args_array_keyword.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\OptionalArgsArrayKeyword;
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
 use Google\Cloud\Dlp\V2\CreateDlpJobRequest;
diff --git a/examples/optional_args_variable.legacy.php b/examples/optional_args_variable.legacy.php
index 37aa6bc..59e85b6 100644
--- a/examples/optional_args_variable.legacy.php
+++ b/examples/optional_args_variable.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\OptionalArgsVariable;
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
 use Google\Cloud\Dlp\V2\InspectConfig;
diff --git a/examples/optional_args_variable.new.php b/examples/optional_args_variable.new.php
index 6880d46..7311be3 100644
--- a/examples/optional_args_variable.new.php
+++ b/examples/optional_args_variable.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\OptionalArgsVariable;
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
 use Google\Cloud\Dlp\V2\CreateDlpJobRequest;
diff --git a/examples/required_and_optional_args.legacy.php b/examples/required_and_optional_args.legacy.php
index b980ec4..cb896e9 100644
--- a/examples/required_and_optional_args.legacy.php
+++ b/examples/required_and_optional_args.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\RequiredAndOptionalArgs;
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
 use Google\Cloud\Dlp\V2\InspectConfig;
diff --git a/examples/required_and_optional_args.new.php b/examples/required_and_optional_args.new.php
index 72a7611..a9bded6 100644
--- a/examples/required_and_optional_args.new.php
+++ b/examples/required_and_optional_args.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\RequiredAndOptionalArgs;
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
 use Google\Cloud\Dlp\V2\CreateDlpJobRequest;
diff --git a/examples/required_args.legacy.php b/examples/required_args.legacy.php
index 7e006ef..6917255 100644
--- a/examples/required_args.legacy.php
+++ b/examples/required_args.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\RequiredArgs;
 
 use Google\Cloud\Dlp\V2\DlpServiceClient;
 
diff --git a/examples/required_args.new.php b/examples/required_args.new.php
index f0730fe..c01586f 100644
--- a/examples/required_args.new.php
+++ b/examples/required_args.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\RequiredArgs;
 
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
 use Google\Cloud\Dlp\V2\CreateDlpJobRequest;
diff --git a/examples/var_typehint.legacy.php b/examples/var_typehint.legacy.php
index 6cfd141..a05c676 100644
--- a/examples/var_typehint.legacy.php
+++ b/examples/var_typehint.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\VarTypehint;
 
 // new client surface doesn't exist (yet)
 use Google\ApiCore\LongRunning\OperationsClient;
diff --git a/examples/var_typehint.new.php b/examples/var_typehint.new.php
index 652819d..a251b10 100644
--- a/examples/var_typehint.new.php
+++ b/examples/var_typehint.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\VarTypehint;
 
 // new client surface doesn't exist (yet)
 use Google\ApiCore\LongRunning\OperationsClient;
diff --git a/examples/vars_defined_elsewhere.legacy.php b/examples/vars_defined_elsewhere.legacy.php
index ef691a6..99ae876 100644
--- a/examples/vars_defined_elsewhere.legacy.php
+++ b/examples/vars_defined_elsewhere.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\VarsDefinedElsewhere;
 
 // new client surface exists
 use Google\Cloud\Dlp\V2\DlpServiceClient;
diff --git a/examples/vars_defined_elsewhere.new.php b/examples/vars_defined_elsewhere.new.php
index 4a78734..c22cbd8 100644
--- a/examples/vars_defined_elsewhere.new.php
+++ b/examples/vars_defined_elsewhere.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\VarsDefinedElsewhere;
 
 // new client surface exists
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
diff --git a/examples/vars_in_constructor.legacy.php b/examples/vars_in_constructor.legacy.php
index 2be7722..fbd6627 100644
--- a/examples/vars_in_constructor.legacy.php
+++ b/examples/vars_in_constructor.legacy.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\VarsInConstructor;
 
 // new client surface exists
 use Google\Cloud\Dlp\V2\DlpServiceClient;
diff --git a/examples/vars_in_constructor.new.php b/examples/vars_in_constructor.new.php
index c73241a..5a211e3 100644
--- a/examples/vars_in_constructor.new.php
+++ b/examples/vars_in_constructor.new.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Google\Cloud\Samples\Dlp;
+namespace Google\Cloud\Samples\VarsInConstructor;
 
 // new client surface exists
 use Google\Cloud\Dlp\V2\Client\DlpServiceClient;
diff --git a/src/TestUtils/CloudFunctionDeploymentTrait.php b/src/TestUtils/CloudFunctionDeploymentTrait.php
index 8c34bbf..26ad046 100644
--- a/src/TestUtils/CloudFunctionDeploymentTrait.php
+++ b/src/TestUtils/CloudFunctionDeploymentTrait.php
@@ -153,7 +153,7 @@ public function getBaseUri()
      * @param int $retries the number of times to retry entry lookup
      * @param int sleep the number of seconds sleep before executing the log lookup
      */
-    private function processFunctionLogs(string $startTime, callable $process, int $retries = null, int $sleep = null)
+    private function processFunctionLogs(string $startTime, callable $process, ?int $retries = null, ?int $sleep = null)
     {
         if (empty(self::$loggingClient)) {
             self::$loggingClient = new LoggingClient([
diff --git a/src/TestUtils/ExponentialBackoffTrait.php b/src/TestUtils/ExponentialBackoffTrait.php
index 456bd93..ad78a0e 100644
--- a/src/TestUtils/ExponentialBackoffTrait.php
+++ b/src/TestUtils/ExponentialBackoffTrait.php
@@ -53,7 +53,7 @@ private function useDeadlineExceededBackoff($retries = null)
         });
     }
 
-    private function useBackoff($retries = null, callable $retryFunction = null)
+    private function useBackoff($retries = null, ?callable $retryFunction = null)
     {
         $backoff = new ExponentialBackoff(
             $retries ?: $this->expontentialBackoffRetryCount,
diff --git a/src/TestUtils/FileUtil.php b/src/TestUtils/FileUtil.php
index 8df98fa..e725bd3 100644
--- a/src/TestUtils/FileUtil.php
+++ b/src/TestUtils/FileUtil.php
@@ -30,14 +30,14 @@ public static function randomName($length)
         return join('', $array);
     }
 
-    public static function cloneDirectoryIntoTmp($projectDir = '.', ProgressBar $progress = null)
+    public static function cloneDirectoryIntoTmp($projectDir = '.', ?ProgressBar $progress = null)
     {
         $tmpDir = sys_get_temp_dir() . '/test-' . self::randomName(8);
         self::copyDir($projectDir, $tmpDir, $progress);
         return $tmpDir;
     }
 
-    public static function copyDir($src, $dst, ProgressBar $progress = null)
+    public static function copyDir($src, $dst, ?ProgressBar $progress = null)
     {
         @mkdir($dst);
         $dir = opendir($src);
diff --git a/src/TestUtils/GcloudWrapper/CloudFunction.php b/src/TestUtils/GcloudWrapper/CloudFunction.php
index ba1667d..e9182f2 100644
--- a/src/TestUtils/GcloudWrapper/CloudFunction.php
+++ b/src/TestUtils/GcloudWrapper/CloudFunction.php
@@ -70,7 +70,7 @@ public function __construct(
         string $entryPoint,
         string $functionSignatureType,
         string $region,
-        string $dir = null
+        ?string $dir = null
     ) {
         $this->projectId = $projectId;
         $this->entryPoint = $entryPoint;
@@ -137,7 +137,7 @@ public function getFunctionName()
      *
      * @return bool true if deployment suceeds, false upon failure
      */
-    public function deploy(array $flags = [], string $trigger = self::DEFAULT_TRIGGER, int $retries = 3, string $channel = null)
+    public function deploy(array $flags = [], string $trigger = self::DEFAULT_TRIGGER, int $retries = 3, ?string $channel = null)
     {
         if ($this->deployed) {
             $this->errorLog('The function has already been deployed.');
@@ -237,7 +237,7 @@ public function getBaseUrl($force = false, $retries = 3)
      * @param array $args
      * @return \Symfony\Component\Process\Process
      */
-    private function gcloudCommand(array $args, string $channel = null)
+    private function gcloudCommand(array $args, ?string $channel = null)
     {
         if (!in_array($channel, [null, 'alpha', 'beta'])) {
             $this->errorLog('gcloud channel must use product (null), "alpha" or "beta". Defaulting to production.');
@@ -271,7 +271,7 @@ private function gcloudCommand(array $args, string $channel = null)
      * @return \Symfony\Component\Process\Process returns the php server process
      * @throws \Symfony\Component\Process\Exception\ProcessFailedException
      */
-    public function run(array $env = [], string $port = self::DEFAULT_PORT, string $phpBin = null)
+    public function run(array $env = [], string $port = self::DEFAULT_PORT, ?string $phpBin = null)
     {
         $this->localUri = 'localhost:' . $port;
 
@@ -306,7 +306,7 @@ public function run(array $env = [], string $port = self::DEFAULT_PORT, string $
      * @return \Symfony\Component\Process\Process returns the php server process
      * @throws \Symfony\Component\Process\Exception\ProcessFailedException
      */
-    public function runCloudEventFunction(string $port = self::DEFAULT_PORT, string $phpBin = null)
+    public function runCloudEventFunction(string $port = self::DEFAULT_PORT, ?string $phpBin = null)
     {
         return $this->run(true, $port, $phpBin);
     }
diff --git a/src/Utils/ExponentialBackoff.php b/src/Utils/ExponentialBackoff.php
index cddff70..b6d68c1 100644
--- a/src/Utils/ExponentialBackoff.php
+++ b/src/Utils/ExponentialBackoff.php
@@ -59,7 +59,7 @@ class ExponentialBackoff
      * @param int $retries [optional] Number of retries for a failed request.
      * @param callable $retryFunction [optional] returns bool for whether or not to retry
      */
-    public function __construct($retries = null, callable $retryFunction = null)
+    public function __construct($retries = null, ?callable $retryFunction = null)
     {
         $this->retries = $retries !== null ? (int) $retries : 3;
         $this->retryFunction = $retryFunction;
diff --git a/src/Utils/Flex/FlexExecCommand.php b/src/Utils/Flex/FlexExecCommand.php
index 3d2163f..d292e3f 100644
--- a/src/Utils/Flex/FlexExecCommand.php
+++ b/src/Utils/Flex/FlexExecCommand.php
@@ -46,7 +46,7 @@ class FlexExecCommand extends Command
     /* @var Gcloud */
     private $gcloud;
 
-    public function __construct(Gcloud $gcloud = null)
+    public function __construct(?Gcloud $gcloud = null)
     {
         parent::__construct();
         $this->gcloud = ($gcloud == null) ? new Gcloud() : $gcloud;
diff --git a/src/Utils/WordPress/Project.php b/src/Utils/WordPress/Project.php
index 087973c..2c592f7 100644
--- a/src/Utils/WordPress/Project.php
+++ b/src/Utils/WordPress/Project.php
@@ -44,7 +44,7 @@ class Project extends BaseProject
     private $filesystem;
     private $wordPressDir;
 
-    public function __construct(InputInterface $input, OutputInterface $output, QuestionHelper $helper = null)
+    public function __construct(InputInterface $input, OutputInterface $output, ?QuestionHelper $helper = null)
     {
         $this->input = $input;
         $this->output = $output;