diff --git a/.github/workflows/phpunit-tests.yml b/.github/workflows/phpunit-tests.yml
index ae4e79a..b52bdba 100644
--- a/.github/workflows/phpunit-tests.yml
+++ b/.github/workflows/phpunit-tests.yml
@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-version: [7.4, 8.4]
+        php-version: [8.0, 8.4]
 
     steps:
       - name: Check out the source code
diff --git a/composer.json b/composer.json
index f71a366..f5c893f 100644
--- a/composer.json
+++ b/composer.json
@@ -5,11 +5,12 @@
 	"homepage": "https://polylang.pro",
 	"type": "library",
 	"require": {
-		"szepeviktor/phpstan-wordpress": "^1.0"
+		"php": "^8.0",
+		"szepeviktor/phpstan-wordpress": "^2.0",
+		"wpsyntex/polylang-stubs": "dev-master"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "^7 || ^9",
-		"wpsyntex/polylang-stubs": "dev-master"
+		"phpunit/phpunit": "^9"
 	},
 	"autoload": {
 		"psr-4": {
diff --git a/src/GuessTypeFromSwitcherAttributes.php b/src/GuessTypeFromSwitcherAttributes.php
index 5394bf9..1375d9e 100644
--- a/src/GuessTypeFromSwitcherAttributes.php
+++ b/src/GuessTypeFromSwitcherAttributes.php
@@ -8,7 +8,6 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\Type;
-use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\StringType;
@@ -28,7 +27,7 @@ private function guessType(Arg $args, Scope $scope) : Type
 			$argsKeys   = [];
 			$argsValues = [];
 
-			if ($argsType instanceof ArrayType) {
+			if ($argsType->isArray()->yes()) {
 				$argsKeys   = $argsType->getKeysArray();
 				$argsValues = $argsType->getValuesArray();
 			}
@@ -42,7 +41,7 @@ private function guessType(Arg $args, Scope $scope) : Type
 				}
 			}
 
-			if ($argsKeys instanceof ConstantArrayType) {
+			if ($argsKeys->isConstantArray()->yes()) {
 				foreach ($argsKeys->getValueTypes() as $index => $key) {
 					if ($key->getValue() !== 'raw') {
 						// Current argument is not 'raw' parameter.
diff --git a/src/ModelLanguagesGetListDynamicMethodReturnTypeExtension.php b/src/ModelLanguagesGetListDynamicMethodReturnTypeExtension.php
index 6fd7768..f4431f9 100644
--- a/src/ModelLanguagesGetListDynamicMethodReturnTypeExtension.php
+++ b/src/ModelLanguagesGetListDynamicMethodReturnTypeExtension.php
@@ -11,7 +11,6 @@
 use PhpParser\Node\Expr\MethodCall;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\MethodReflection;
-use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\IntersectionType;
@@ -60,7 +59,7 @@ public function getTypeFromMethodCall( MethodReflection $methodReflection, Metho
 
 				$fieldsType = $type->getOffsetValueType( $fieldsInst );
 
-				if ( ! $fieldsType instanceof ConstantStringType ) {
+				if ( $fieldsType->isString()->no() ) {
 					// The 'field' argument is not a string.
 					return new ArrayType( new IntegerType(), new ObjectType( PLL_Language::class ) );
 				}
@@ -70,10 +69,10 @@ public function getTypeFromMethodCall( MethodReflection $methodReflection, Metho
 			}
 		}
 
-		if ( ! isset( $fieldsValue ) && $argumentType instanceof ArrayType ) {
+		if ( ! isset( $fieldsValue ) && $argumentType->isArray()->yes() ) {
 			$argumentKeys = $argumentType->getKeysArray();
 
-			if ( $argumentKeys instanceof ConstantArrayType ) {
+			if ( $argumentKeys->isConstantArray()->yes() ) {
 				$argumentKeysTypes = $argumentKeys->getValueTypes();
 
 				if( empty( $argumentKeysTypes ) ) {
@@ -88,7 +87,7 @@ public function getTypeFromMethodCall( MethodReflection $methodReflection, Metho
 
 					$fieldsType = $argumentType->getValuesArray()->getValueTypes()[ $index ];
 
-					if ( ! $fieldsType instanceof ConstantStringType ) {
+					if ( $fieldsType->isString()->no() ) {
 						// The 'field' argument is not a string.
 						return new ArrayType( new IntegerType(), new ObjectType( PLL_Language::class ) );
 					}
diff --git a/src/OptionsGetDynamicMethodReturnTypeExtension.php b/src/OptionsGetDynamicMethodReturnTypeExtension.php
index b79df52..1b5995c 100644
--- a/src/OptionsGetDynamicMethodReturnTypeExtension.php
+++ b/src/OptionsGetDynamicMethodReturnTypeExtension.php
@@ -75,11 +75,9 @@ public function getTypeFromMethodCall( MethodReflection $methodReflection, Metho
 				case 'post_types':
 				case 'sync':
 				case 'taxonomies':
-					$returnType[] = AccessoryArrayListType::intersectWith(
-						new ArrayType(
-							new IntegerType(),
-							$this->getNonFalsyStringType()
-						)
+					$returnType[] = new ArrayType(
+						new IntegerType(),
+						$this->getNonFalsyStringType()
 					);
 					break;