diff --git a/composer.json b/composer.json
index 172013d..57cbd22 100644
--- a/composer.json
+++ b/composer.json
@@ -37,7 +37,7 @@
         "simplesamlphp/assert": "^1.1"
     },
     "require-dev": {
-        "simplesamlphp/simplesamlphp-test-framework": "^1.5"
+        "simplesamlphp/simplesamlphp-test-framework": "^1.6"
     },
     "support": {
         "issues": "https://github.com/simplesamlphp/xml-common/issues",
diff --git a/src/TestUtils/SchemaValidationTestTrait.php b/src/TestUtils/SchemaValidationTestTrait.php
index c9ebf8d..bf5048e 100644
--- a/src/TestUtils/SchemaValidationTestTrait.php
+++ b/src/TestUtils/SchemaValidationTestTrait.php
@@ -7,6 +7,7 @@
 use DOMDocument;
 use Exception;
 use LibXMLError; // Officially spelled with a lower-case `l`, but that breaks composer-require-checker
+use PHPUnit\Framework\Attributes\Depends;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XML\Exception\SchemaViolationException;
 use XMLReader;
@@ -37,9 +38,8 @@ trait SchemaValidationTestTrait
 
     /**
      * Test schema validation.
-     *
-     * @depends testSerialization
      */
+    #[Depends('testSerialization')]
     public function testSchemaValidation(): void
     {
         if (!class_exists(self::$testedClass)) {
diff --git a/src/TestUtils/SerializableElementTestTrait.php b/src/TestUtils/SerializableElementTestTrait.php
index 27736a1..ede744e 100644
--- a/src/TestUtils/SerializableElementTestTrait.php
+++ b/src/TestUtils/SerializableElementTestTrait.php
@@ -5,6 +5,7 @@
 namespace SimpleSAML\XML\TestUtils;
 
 use DOMDocument;
+use PHPUnit\Framework\Attributes\Depends;
 
 use function class_exists;
 
@@ -56,10 +57,9 @@ public function testUnmarshalling(): void
 
     /**
      * Test serialization / unserialization.
-     *
-     * @depends testMarshalling
-     * @depends testUnmarshalling
      */
+    #[Depends('testMarshalling')]
+    #[Depends('testUnmarshalling')]
     public function testSerialization(): void
     {
         if (!class_exists(self::$testedClass)) {
diff --git a/tests/XML/Base64ElementTraitTest.php b/tests/XML/Base64ElementTraitTest.php
index 8765f81..b642fe6 100644
--- a/tests/XML/Base64ElementTraitTest.php
+++ b/tests/XML/Base64ElementTraitTest.php
@@ -4,6 +4,7 @@
 
 namespace SimpleSAML\Test\XML;
 
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use SimpleSAML\Test\XML\XMLDumper;
 use SimpleSAML\XML\DOMDocumentFactory;
@@ -65,8 +66,8 @@ public function testUnmarshalling(): void
 
     /**
      * @param non-empty-string $xml
-     * @dataProvider provideBase64Cases
      */
+    #[DataProvider('provideBase64Cases')]
     public function testBase64Cases(string $xml): void
     {
         $xmlRepresentation = DOMDocumentFactory::fromString($xml);