diff --git a/.github/workflows/analyzers.yaml b/.github/workflows/analyzers.yaml
index 1f40ed6..c5d9d9a 100644
--- a/.github/workflows/analyzers.yaml
+++ b/.github/workflows/analyzers.yaml
@@ -7,7 +7,8 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ubuntu-latest]
-                php-versions: ['8.1', '8.2', '8.3']
+                php-versions: ['8.2', '8.3']
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.github/workflows/code-style.yaml b/.github/workflows/code-style.yaml
index 089eaa5..a8a0975 100644
--- a/.github/workflows/code-style.yaml
+++ b/.github/workflows/code-style.yaml
@@ -7,7 +7,8 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ubuntu-latest]
-                php-versions: ['8.1', '8.2', '8.3']
+                php-versions: ['8.2', '8.3', '8.4']
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 7970d91..b471eec 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -7,7 +7,8 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ubuntu-latest]
-                php-versions: ['8.1', '8.2', '8.3']
+                php-versions: ['8.2', '8.3', '8.4']
+                composer-options: ['--ignore-platform-req=php+']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
@@ -20,6 +21,6 @@ jobs:
                   tools: 'composer:v2'
                   extensions: pcov, mbstring, posix, dom, soap
             - name: Install dependencies
-              run: composer update --prefer-dist --no-progress --no-suggest
+              run: composer update --prefer-dist --no-progress --no-suggest ${{ matrix.composer-options }}
             - name: Run the tests
               run: ./vendor/bin/phpunit
diff --git a/.phive/phars.xml b/.phive/phars.xml
index 7c19d43..76dea74 100644
--- a/.phive/phars.xml
+++ b/.phive/phars.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phive xmlns="https://phar.io/phive">
-  <phar name="psalm" version="^5.16.0" installed="5.16.0" location="./tools/psalm.phar" copy="true"/>
-  <phar name="php-cs-fixer" version="^3.13.0" installed="3.39.0" location="./tools/php-cs-fixer.phar" copy="true"/>
+  <phar name="psalm" version="^5.16.0" installed="5.26.1" location="./tools/psalm.phar" copy="true"/>
+  <phar name="php-cs-fixer" version="^3.13.0" installed="3.64.0" location="./tools/php-cs-fixer.phar" copy="true"/>
 </phive>
diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index b2fc9eb..7faf356 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -53,5 +53,6 @@
         'static_lambda' => true,
         'strict_comparison' => true,
         'strict_param' => true,
+        'nullable_type_declaration_for_default_null_value' => true,
     ])
 ;
diff --git a/composer.json b/composer.json
index d8c228d..90920ff 100644
--- a/composer.json
+++ b/composer.json
@@ -20,11 +20,11 @@
         }
     ],
     "require": {
-        "php": "~8.1.0 || ~8.2.0 || ~8.3.0",
+        "php": "~8.2.0 || ~8.3.0 || ~8.4.0",
         "ext-dom": "*",
-        "veewee/xml": "^2.2 || ^3.0"
+        "veewee/xml": "^3.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.5"
+        "phpunit/phpunit": "^10.0"
     }
 }
diff --git a/phpunit.xml b/phpunit.xml
index 07df353..5ec8f19 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,4 +1,7 @@
-<phpunit bootstrap="./tests/bootstrap.php" colors="true">
+<phpunit bootstrap="./tests/bootstrap.php" colors="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+    displayDetailsOnPhpunitDeprecations="true">
     <testsuites>
         <testsuite name="Unit">
             <directory>./tests/Unit</directory>
diff --git a/tests/Unit/XmlnsTest.php b/tests/Unit/XmlnsTest.php
index 7ce7cc5..e25637e 100644
--- a/tests/Unit/XmlnsTest.php
+++ b/tests/Unit/XmlnsTest.php
@@ -20,7 +20,7 @@ public function test_it_knows_some_xmlnses(callable $factory, string $uri): void
         static::assertSame($xmlns->value(), $uri);
     }
 
-    public function provideKnownXmlnses()
+    public static function provideKnownXmlnses()
     {
         yield 'wsdl' => [
             static fn () => Xmlns::wsdl(),
diff --git a/tools/php-cs-fixer.phar b/tools/php-cs-fixer.phar
index 9a03f3e..d071fa5 100755
Binary files a/tools/php-cs-fixer.phar and b/tools/php-cs-fixer.phar differ
diff --git a/tools/psalm.phar b/tools/psalm.phar
index 2e4956a..24b9ae3 100755
Binary files a/tools/psalm.phar and b/tools/psalm.phar differ