diff --git a/.github/workflows/ci.yaml b/.github/workflows/backend-ci.yaml
similarity index 97%
rename from .github/workflows/ci.yaml
rename to .github/workflows/backend-ci.yaml
index 0212f4458d..a11c80d718 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/backend-ci.yaml
@@ -43,8 +43,8 @@ jobs:
       matrix:
         php:
           - '7.4'
-          - '8.0'
-          - '8.1'
+          - '8.3'
+          - '8.4'
 
     steps:
       - uses: actions/checkout@v4
@@ -95,8 +95,8 @@ jobs:
       matrix:
         php:
           - '7.4'
-          - '8.0'
-          - '8.1'
+          - '8.3'
+          - '8.4'
 
     steps:
       -   uses: actions/checkout@v3
@@ -150,8 +150,8 @@ jobs:
       matrix:
         php:
           - '7.4'
-          - '8.0'
-          - '8.1'
+          - '8.3'
+          - '8.4'
 
     steps:
       -   uses: actions/checkout@v3
diff --git a/phpstan-baseline-7.4.neon b/phpstan-baseline-7.4.neon
index beddd115ca..53fa25bae8 100644
--- a/phpstan-baseline-7.4.neon
+++ b/phpstan-baseline-7.4.neon
@@ -282,3 +282,15 @@ parameters:
 			identifier: argument.type
 			count: 1
 			path: src/bundle/Templating/Twig/UniversalDiscoveryExtension.php
+
+		-
+			message: '#^Call to method Ibexa\\AdminUi\\Form\\DataTransformer\\LanguageTransformer\:\:transform\(\) on a separate line has no effect\.$#'
+			identifier: method.resultUnused
+			count: 1
+			path: tests/lib/Form/DataTransformer/LanguageTransformerTest.php
+
+		-
+			message: '#^Call to method Ibexa\\AdminUi\\Form\\DataTransformer\\ContentInfoTransformer\:\:transform\(\) on a separate line has no effect\.$#'
+			identifier: method.resultUnused
+			count: 1
+			path: tests/lib/Form/DataTransformer/ContentInfoTransformerTest.php
diff --git a/phpstan-baseline-8.3.neon b/phpstan-baseline-8.3.neon
index 9c45740199..7ebbd5bbb2 100644
--- a/phpstan-baseline-8.3.neon
+++ b/phpstan-baseline-8.3.neon
@@ -199,3 +199,15 @@ parameters:
 			message: "#^Deprecated in PHP 8\\.0\\: Required parameter \\$twig follows optional parameter \\$name\\.$#"
 			count: 1
 			path: tests/lib/Tab/TabRegistryTest.php
+
+		-
+			message: '#^Call to method Ibexa\\AdminUi\\Form\\DataTransformer\\LanguageTransformer\:\:transform\(\) on a separate line has no effect\.$#'
+			identifier: method.resultUnused
+			count: 1
+			path: tests/lib/Form/DataTransformer/LanguageTransformerTest.php
+
+		-
+			message: '#^Call to method Ibexa\\AdminUi\\Form\\DataTransformer\\ContentInfoTransformer\:\:transform\(\) on a separate line has no effect\.$#'
+			identifier: method.resultUnused
+			count: 1
+			path: tests/lib/Form/DataTransformer/ContentInfoTransformerTest.php
diff --git a/phpstan-baseline-8.0.neon b/phpstan-baseline-8.4.neon
similarity index 94%
rename from phpstan-baseline-8.0.neon
rename to phpstan-baseline-8.4.neon
index 199f1d4121..9c45740199 100644
--- a/phpstan-baseline-8.0.neon
+++ b/phpstan-baseline-8.4.neon
@@ -199,13 +199,3 @@ parameters:
 			message: "#^Deprecated in PHP 8\\.0\\: Required parameter \\$twig follows optional parameter \\$name\\.$#"
 			count: 1
 			path: tests/lib/Tab/TabRegistryTest.php
-
-		-
-		    message: "#^Parameter \\#1 \\$iterator of function iterator_to_array expects Traversable, iterable\\<Ibexa\\\\Core\\\\MVC\\\\Symfony\\\\SiteAccess\\> given\\.$#"
-		    count: 1
-		    path: src/lib/Siteaccess/SiteaccessResolver.php
-
-		-
-		    message: "#^Parameter \\#1 \\$iterator of function iterator_to_array expects Traversable, iterable\\<string, Ibexa\\\\AdminUi\\\\Form\\\\Data\\\\FieldDefinitionData\\> given\\.$#"
-		    count: 1
-		    path: tests/lib/Form/Data/ContentTypeDataTest.php
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index ed08d93477..9f575ee7c7 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -15370,12 +15370,6 @@ parameters:
 			count: 1
 			path: tests/lib/Form/DataMapper/SelectionUpdateMapperTest.php
 
-		-
-			message: '#^Call to method Ibexa\\AdminUi\\Form\\DataTransformer\\ContentInfoTransformer\:\:transform\(\) on a separate line has no effect\.$#'
-			identifier: method.resultUnused
-			count: 1
-			path: tests/lib/Form/DataTransformer/ContentInfoTransformerTest.php
-
 		-
 			message: '#^Method Ibexa\\Tests\\AdminUi\\Form\\DataTransformer\\ContentInfoTransformerTest\:\:reverseTransformDataProvider\(\) return type has no value type specified in iterable type array\.$#'
 			identifier: missingType.iterableValue
diff --git a/phpstan-baseline.neon.php b/phpstan-baseline.neon.php
index da44dc862c..4fc0d69823 100644
--- a/phpstan-baseline.neon.php
+++ b/phpstan-baseline.neon.php
@@ -9,10 +9,10 @@
 $includes = [];
 if (PHP_VERSION_ID < 80000) {
     $includes[] = __DIR__ . '/phpstan-baseline-7.4.neon';
-} elseif (PHP_VERSION_ID < 80300) {
-    $includes[] = __DIR__ . '/phpstan-baseline-8.0.neon';
-} else {
+} else if (PHP_VERSION_ID < 80400) {
     $includes[] = __DIR__ . '/phpstan-baseline-8.3.neon';
+} else {
+    $includes[] = __DIR__ . '/phpstan-baseline-8.4.neon';
 }
 
 $config = [];
diff --git a/src/lib/Form/Factory/FormFactory.php b/src/lib/Form/Factory/FormFactory.php
index ca74984688..8584b4421a 100644
--- a/src/lib/Form/Factory/FormFactory.php
+++ b/src/lib/Form/Factory/FormFactory.php
@@ -1071,7 +1071,7 @@ public function removeContentDraft(
      * @return \Symfony\Component\Form\FormInterface<\Ibexa\AdminUi\Form\Data\Notification\NotificationSelectionData|null>
      */
     public function deleteNotification(
-        NotificationSelectionData $data = null,
+        ?NotificationSelectionData $data = null,
         ?string $name = null
     ): FormInterface {
         $name = $name ?: StringUtil::fqcnToBlockPrefix(NotificationSelectionType::class);
diff --git a/tests/lib/Form/DataTransformer/LanguageTransformerTest.php b/tests/lib/Form/DataTransformer/LanguageTransformerTest.php
index ac179e124a..3ed4884700 100644
--- a/tests/lib/Form/DataTransformer/LanguageTransformerTest.php
+++ b/tests/lib/Form/DataTransformer/LanguageTransformerTest.php
@@ -52,7 +52,6 @@ public function testTransformWithInvalidInput($value): void
         $this->expectException(TransformationFailedException::class);
         $this->expectExceptionMessage('Expected a ' . Language::class . ' object.');
 
-        /** @phpstan-ignore method.resultUnused */
         $transformer->transform($value);
     }