diff --git a/composer.json b/composer.json
index e7c76586b..7dd0447df 100644
--- a/composer.json
+++ b/composer.json
@@ -49,17 +49,17 @@
 	"require": {
 		"php": "^8.2",
 		"ext-mbstring": "*",
-		"chillerlan/php-settings-container": "^3.2"
+		"chillerlan/php-settings-container": "^3.2.1"
 	},
 	"require-dev": {
-		"chillerlan/php-authenticator": "^5.1",
+		"chillerlan/php-authenticator": "^5.2.1",
 		"intervention/image": "^3.7",
 		"phpbench/phpbench": "^1.2.15",
 		"phan/phan": "^5.4",
 		"phpunit/phpunit": "^11.2",
 		"phpmd/phpmd": "^2.15",
 		"setasign/fpdf": "^1.8.2",
-		"squizlabs/php_codesniffer": "^3.9"
+		"squizlabs/php_codesniffer": "^3.10"
 	},
 	"suggest": {
 		"chillerlan/php-authenticator": "Yet another Google authenticator! Also creates URIs for mobile apps.",
diff --git a/examples/custom_output.php b/examples/custom_output.php
index 25bac3f80..69ec5737f 100644
--- a/examples/custom_output.php
+++ b/examples/custom_output.php
@@ -48,7 +48,7 @@ class MyCustomOutput extends QROutputAbstract{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null):string{
+	public function dump(string|null $file = null):string{
 		$output = '';
 
 		for($y = 0; $y < $this->moduleCount; $y++){
diff --git a/examples/imageWithLogo.php b/examples/imageWithLogo.php
index 2f159c773..35b447535 100644
--- a/examples/imageWithLogo.php
+++ b/examples/imageWithLogo.php
@@ -30,7 +30,7 @@ class QRImageWithLogo extends QRGdImagePNG{
 	 * @return string
 	 * @throws \chillerlan\QRCode\Output\QRCodeOutputException
 	 */
-	public function dump(string $file = null, string $logo = null):string{
+	public function dump(string|null $file = null, string|null $logo = null):string{
 		// set returnResource to true to skip further processing for now
 		$this->options->returnResource = true;
 
diff --git a/examples/imageWithText.php b/examples/imageWithText.php
index 0f68870c5..be71e220b 100644
--- a/examples/imageWithText.php
+++ b/examples/imageWithText.php
@@ -26,7 +26,7 @@ class QRImageWithText extends QRGdImagePNG{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null, string $text = null):string{
+	public function dump(string|null $file = null, string|null $text = null):string{
 		// set returnResource to true to skip further processing for now
 		$this->options->returnResource = true;
 
diff --git a/examples/imagickConvertSVGtoPNG.php b/examples/imagickConvertSVGtoPNG.php
index 11734d82a..c4351f39c 100644
--- a/examples/imagickConvertSVGtoPNG.php
+++ b/examples/imagickConvertSVGtoPNG.php
@@ -47,7 +47,7 @@ class SVGConvert extends QRMarkupSVG{
 	}
 
 	/** @inheritDoc */
-	public function dump(string $file = null):string{
+	public function dump(string|null $file = null):string{
 		$base64 = $this->options->outputBase64;
 		// we don't want the SVG in base64
 		$this->options->outputBase64 = false;
diff --git a/examples/imagickWithLogo.php b/examples/imagickWithLogo.php
index 39ba164f5..21141a848 100644
--- a/examples/imagickWithLogo.php
+++ b/examples/imagickWithLogo.php
@@ -28,7 +28,7 @@ class QRImagickWithLogo extends QRImagick{
 	 * @inheritDoc
 	 * @throws \chillerlan\QRCode\Output\QRCodeOutputException
 	 */
-	public function dump(string $file = null):string{
+	public function dump(string|null $file = null):string{
 		// set returnResource to true to skip further processing for now
 		$this->options->returnResource = true;
 
diff --git a/src/Common/ECICharset.php b/src/Common/ECICharset.php
index 0c98e36da..09f90c19a 100644
--- a/src/Common/ECICharset.php
+++ b/src/Common/ECICharset.php
@@ -118,7 +118,7 @@ final class ECICharset{
 	 * @see \mb_convert_encoding()
 	 * @see \iconv()
 	 */
-	public function getName():?string{
+	public function getName():string|null{
 		return (self::MB_ENCODINGS[$this->charsetID] ?? null);
 	}
 
diff --git a/src/Common/GenericGFPoly.php b/src/Common/GenericGFPoly.php
index ae361b9d0..7aeafc96a 100644
--- a/src/Common/GenericGFPoly.php
+++ b/src/Common/GenericGFPoly.php
@@ -35,7 +35,7 @@ final class GenericGFPoly{
 	 * @throws \chillerlan\QRCode\QRCodeException if argument is null or empty, or if leading coefficient is 0 and this
 	 *                                            is not a constant polynomial (that is, it is not the monomial "0")
 	 */
-	public function __construct(array $coefficients, int $degree = null){
+	public function __construct(array $coefficients, int|null $degree = null){
 		$degree ??= 0;
 
 		if(empty($coefficients)){
diff --git a/src/Common/Version.php b/src/Common/Version.php
index fe7240f8a..15a4d4a9b 100644
--- a/src/Common/Version.php
+++ b/src/Common/Version.php
@@ -257,7 +257,7 @@ final class Version{
 	/**
 	 * the version pattern for the given version
 	 */
-	public function getVersionPattern():?int{
+	public function getVersionPattern():int|null{
 		return (self::VERSION_PATTERN[$this->version] ?? null);
 	}
 
diff --git a/src/Data/QRMatrix.php b/src/Data/QRMatrix.php
index bcf141cda..9bf3d0b61 100755
--- a/src/Data/QRMatrix.php
+++ b/src/Data/QRMatrix.php
@@ -110,12 +110,12 @@ class QRMatrix{
 	/**
 	 * the matrix version - always set in QRMatrix, may be null in BitMatrix
 	 */
-	protected ?Version $version = null;
+	protected Version|null $version = null;
 
 	/**
 	 * the current ECC level - always set in QRMatrix, may be null in BitMatrix
 	 */
-	protected ?EccLevel $eccLevel = null;
+	protected EccLevel|null $eccLevel = null;
 
 	/**
 	 * the mask pattern that was used in the most recent operation, set via:
@@ -124,7 +124,7 @@ class QRMatrix{
 	 * - QRMatrix::mask()
 	 * - BitMatrix::readFormatInformation()
 	 */
-	protected ?MaskPattern $maskPattern = null;
+	protected MaskPattern|null $maskPattern = null;
 
 	/**
 	 * the size (side length) of the matrix, including quiet zone (if created)
@@ -175,7 +175,7 @@ class QRMatrix{
 	 *
 	 * @return int[][]|bool[][]
 	 */
-	public function getMatrix(bool $boolean = null):array{
+	public function getMatrix(bool|null $boolean = null):array{
 
 		if($boolean !== true){
 			return $this->matrix;
@@ -193,21 +193,21 @@ class QRMatrix{
 	/**
 	 * Returns the current version number
 	 */
-	public function getVersion():?Version{
+	public function getVersion():Version|null{
 		return $this->version;
 	}
 
 	/**
 	 * Returns the current ECC level
 	 */
-	public function getEccLevel():?EccLevel{
+	public function getEccLevel():EccLevel|null{
 		return $this->eccLevel;
 	}
 
 	/**
 	 * Returns the current mask pattern
 	 */
-	public function getMaskPattern():?MaskPattern{
+	public function getMaskPattern():MaskPattern|null{
 		return $this->maskPattern;
 	}
 
@@ -342,7 +342,7 @@ class QRMatrix{
 	 *   7 # 3
 	 *   6 5 4
 	 */
-	public function checkNeighbours(int $x, int $y, int $M_TYPE = null):int{
+	public function checkNeighbours(int $x, int $y, int|null $M_TYPE = null):int{
 		$bits = 0;
 
 		foreach($this::neighbours as $bit => [$ix, $iy]){
@@ -507,7 +507,7 @@ class QRMatrix{
 	 *
 	 * ISO/IEC 18004:2000 Section 8.9
 	 */
-	public function setFormatInfo(MaskPattern $maskPattern = null):static{
+	public function setFormatInfo(MaskPattern|null $maskPattern = null):static{
 		$this->maskPattern = $maskPattern;
 		$bits              = 0; // sets all format fields to false (test mode)
 
@@ -633,7 +633,7 @@ class QRMatrix{
 	 *
 	 * @throws \chillerlan\QRCode\Data\QRCodeDataException
 	 */
-	public function setLogoSpace(int $width, int $height = null, int $startX = null, int $startY = null):static{
+	public function setLogoSpace(int $width, int|null $height = null, int|null $startX = null, int|null $startY = null):static{
 		$height ??= $width;
 
 		// if width and height happen to be negative or 0 (default value), just return - nothing to do
diff --git a/src/Decoder/BitMatrix.php b/src/Decoder/BitMatrix.php
index 1aec32ac6..2ec302a89 100644
--- a/src/Decoder/BitMatrix.php
+++ b/src/Decoder/BitMatrix.php
@@ -251,7 +251,7 @@ final class BitMatrix extends QRMatrix{
 	/**
 	 * Returns information about the format it specifies, or null if it doesn't seem to match any known pattern
 	 */
-	private function doDecodeFormatInformation(int $maskedFormatInfo1, int $maskedFormatInfo2):?int{
+	private function doDecodeFormatInformation(int $maskedFormatInfo1, int $maskedFormatInfo2):int|null{
 		$bestDifference = PHP_INT_MAX;
 		$bestFormatInfo = 0;
 
@@ -347,7 +347,7 @@ final class BitMatrix extends QRMatrix{
 	/**
 	 * Decodes the version information from the given bit sequence, returns null if no valid match is found.
 	 */
-	private function decodeVersionInformation(int $versionBits):?Version{
+	private function decodeVersionInformation(int $versionBits):Version|null{
 		$bestDifference = PHP_INT_MAX;
 		$bestVersion    = 0;
 
@@ -414,7 +414,7 @@ final class BitMatrix extends QRMatrix{
 	 * @codeCoverageIgnore
 	 * @throws \chillerlan\QRCode\Data\QRCodeDataException
 	 */
-	public function setQuietZone(int $quietZoneSize = null):static{
+	public function setQuietZone(int|null $quietZoneSize = null):static{
 		throw new QRCodeDataException('not supported');
 	}
 
@@ -422,7 +422,7 @@ final class BitMatrix extends QRMatrix{
 	 * @codeCoverageIgnore
 	 * @throws \chillerlan\QRCode\Data\QRCodeDataException
 	 */
-	public function setLogoSpace(int $width, int $height = null, int $startX = null, int $startY = null):static{
+	public function setLogoSpace(int $width, int|null $height = null, int|null $startX = null, int|null $startY = null):static{
 		throw new QRCodeDataException('not supported');
 	}
 
diff --git a/src/Decoder/Decoder.php b/src/Decoder/Decoder.php
index 3d8dc39a7..a6d129d4c 100644
--- a/src/Decoder/Decoder.php
+++ b/src/Decoder/Decoder.php
@@ -31,9 +31,9 @@ final class Decoder{
 	 * @var \chillerlan\QRCode\QROptions|\chillerlan\Settings\SettingsContainerInterface
 	 */
 	private SettingsContainerInterface|QROptions   $options;
-	private ?Version                               $version     = null;
-	private ?EccLevel                              $eccLevel    = null;
-	private ?MaskPattern                           $maskPattern = null;
+	private Version|null                           $version     = null;
+	private EccLevel|null                          $eccLevel    = null;
+	private MaskPattern|null                       $maskPattern = null;
 	private BitBuffer                              $bitBuffer;
 
 	public function __construct(SettingsContainerInterface|QROptions $options = new QROptions){
diff --git a/src/Decoder/DecoderResult.php b/src/Decoder/DecoderResult.php
index 02b4d7931..4b64b51f6 100644
--- a/src/Decoder/DecoderResult.php
+++ b/src/Decoder/DecoderResult.php
@@ -41,7 +41,7 @@ final class DecoderResult{
 	/**
 	 * DecoderResult constructor.
 	 */
-	public function __construct(iterable $properties = null){
+	public function __construct(iterable|null $properties = null){
 
 		if(!empty($properties)){
 
diff --git a/src/Detector/AlignmentPatternFinder.php b/src/Detector/AlignmentPatternFinder.php
index ca62c6f36..b4ee41fdf 100644
--- a/src/Detector/AlignmentPatternFinder.php
+++ b/src/Detector/AlignmentPatternFinder.php
@@ -58,7 +58,7 @@ final class AlignmentPatternFinder{
 	 *
 	 * @return \chillerlan\QRCode\Detector\AlignmentPattern|null
 	 */
-	public function find(int $startX, int $startY, int $width, int $height):?AlignmentPattern{
+	public function find(int $startX, int $startY, int $width, int $height):AlignmentPattern|null{
 		$maxJ       = ($startX + $width);
 		$middleI    = ($startY + ($height / 2));
 		$stateCount = [];
@@ -173,7 +173,7 @@ final class AlignmentPatternFinder{
 	 *
 	 * @return \chillerlan\QRCode\Detector\AlignmentPattern|null if we have found the same pattern twice, or null if not
 	 */
-	private function handlePossibleCenter(array $stateCount, int $i, int $j):?AlignmentPattern{
+	private function handlePossibleCenter(array $stateCount, int $i, int $j):AlignmentPattern|null{
 		$stateCountTotal = ($stateCount[0] + $stateCount[1] + $stateCount[2]);
 		$centerJ         = $this->centerFromEnd($stateCount, $j);
 		$centerI         = $this->crossCheckVertical($i, (int)$centerJ, (2 * $stateCount[1]), $stateCountTotal);
@@ -222,7 +222,7 @@ final class AlignmentPatternFinder{
 	 *
 	 * @return float|null vertical center of alignment pattern, or null if not found
 	 */
-	private function crossCheckVertical(int $startI, int $centerJ, int $maxCount, int $originalStateCountTotal):?float{
+	private function crossCheckVertical(int $startI, int $centerJ, int $maxCount, int $originalStateCountTotal):float|null{
 		$maxI          = $this->matrix->getSize();
 		$stateCount    = [];
 		$stateCount[0] = 0;
diff --git a/src/Detector/Detector.php b/src/Detector/Detector.php
index e43798b9f..a4a6d34c8 100644
--- a/src/Detector/Detector.php
+++ b/src/Detector/Detector.php
@@ -275,7 +275,7 @@ final class Detector{
 		int $estAlignmentX,
 		int $estAlignmentY,
 		float $allowanceFactor
-	):?AlignmentPattern{
+	):AlignmentPattern|null{
 		// Look for an alignment pattern (3 modules in size) around where it should be
 		$dimension           = $this->matrix->getSize();
 		$allowance           = (int)($allowanceFactor * $overallEstModuleSize);
@@ -305,11 +305,11 @@ final class Detector{
 	 *
 	 */
 	private function createTransform(
-		FinderPattern    $nw,
-		FinderPattern    $ne,
-		FinderPattern    $sw,
-		int              $size,
-		AlignmentPattern $ap = null
+		FinderPattern         $nw,
+		FinderPattern         $ne,
+		FinderPattern         $sw,
+		int                   $size,
+		AlignmentPattern|null $ap = null
 	):PerspectiveTransform{
 		$dimMinusThree = ($size - 3.5);
 
diff --git a/src/Detector/FinderPattern.php b/src/Detector/FinderPattern.php
index 79e13e9c6..2c0ebd439 100644
--- a/src/Detector/FinderPattern.php
+++ b/src/Detector/FinderPattern.php
@@ -27,7 +27,7 @@ final class FinderPattern extends ResultPoint{
 	/**
 	 *
 	 */
-	public function __construct(float $posX, float $posY, float $estimatedModuleSize, int $count = null){
+	public function __construct(float $posX, float $posY, float $estimatedModuleSize, int|null $count = null){
 		parent::__construct($posX, $posY, $estimatedModuleSize);
 
 		$this->count = ($count ?? 1);
diff --git a/src/Detector/FinderPatternFinder.php b/src/Detector/FinderPatternFinder.php
index 755d08c27..03de4a1a8 100644
--- a/src/Detector/FinderPatternFinder.php
+++ b/src/Detector/FinderPatternFinder.php
@@ -330,7 +330,7 @@ final class FinderPatternFinder{
 	 * @return float|null vertical center of finder pattern, or null if not found
 	 * @noinspection DuplicatedCode
 	 */
-	private function crossCheckVertical(int $startI, int $centerJ, int $maxCount, int $originalStateCountTotal):?float{
+	private function crossCheckVertical(int $startI, int $centerJ, int $maxCount, int $originalStateCountTotal):float|null{
 		$maxI       = $this->matrix->getSize();
 		$stateCount = $this->getCrossCheckStateCount();
 
@@ -414,7 +414,7 @@ final class FinderPatternFinder{
 	 * check a vertical cross-check and locate the real center of the alignment pattern.
 	 * @noinspection DuplicatedCode
 	 */
-	private function crossCheckHorizontal(int $startJ, int $centerI, int $maxCount, int $originalStateCountTotal):?float{
+	private function crossCheckHorizontal(int $startJ, int $centerI, int $maxCount, int $originalStateCountTotal):float|null{
 		$maxJ       = $this->matrix->getSize();
 		$stateCount = $this->getCrossCheckStateCount();
 
diff --git a/src/Detector/PerspectiveTransform.php b/src/Detector/PerspectiveTransform.php
index 4f1f6547a..ec4b2fba2 100644
--- a/src/Detector/PerspectiveTransform.php
+++ b/src/Detector/PerspectiveTransform.php
@@ -152,7 +152,7 @@ final class PerspectiveTransform{
 	/**
 	 * @return array[] [$xValues, $yValues]
 	 */
-	public function transformPoints(array $xValues, array $yValues = null):array{
+	public function transformPoints(array $xValues, array|null $yValues = null):array{
 		$max = count($xValues);
 
 		if($yValues !== null){ // unused
diff --git a/src/Output/QREps.php b/src/Output/QREps.php
index d60f1c22c..75f10ecdb 100644
--- a/src/Output/QREps.php
+++ b/src/Output/QREps.php
@@ -101,7 +101,7 @@ class QREps extends QROutputAbstract{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null):string{
+	public function dump(string|null $file = null):string{
 		[$width, $height] = $this->getOutputDimensions();
 
 		$eps = [
diff --git a/src/Output/QRFpdf.php b/src/Output/QRFpdf.php
index 35cf7e555..989724e4f 100644
--- a/src/Output/QRFpdf.php
+++ b/src/Output/QRFpdf.php
@@ -29,8 +29,8 @@ class QRFpdf extends QROutputAbstract{
 
 	final public const MIME_TYPE = 'application/pdf';
 
-	protected FPDF   $fpdf;
-	protected ?array $prevColor = null;
+	protected FPDF       $fpdf;
+	protected array|null $prevColor = null;
 
 	/**
 	 * QRFpdf constructor.
@@ -64,7 +64,7 @@ class QRFpdf extends QROutputAbstract{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null, FPDF $fpdf = null):string|FPDF{
+	public function dump(string|null $file = null, FPDF|null $fpdf = null):string|FPDF{
 		$this->fpdf = ($fpdf ?? $this->initFPDF());
 
 		if($this::moduleValueIsValid($this->options->bgColor)){
diff --git a/src/Output/QRGdImage.php b/src/Output/QRGdImage.php
index e58cbae24..3125672a0 100644
--- a/src/Output/QRGdImage.php
+++ b/src/Output/QRGdImage.php
@@ -144,7 +144,7 @@ abstract class QRGdImage extends QROutputAbstract{
 	 *
 	 * @throws \ErrorException
 	 */
-	public function dump(string $file = null):string|GdImage{
+	public function dump(string|null $file = null):string|GdImage{
 
 		set_error_handler(function(int $errno, string $errstr):bool{
 			throw new ErrorException($errstr, $errno);
diff --git a/src/Output/QRImagick.php b/src/Output/QRImagick.php
index 4ba43e4eb..387fcdbad 100644
--- a/src/Output/QRImagick.php
+++ b/src/Output/QRImagick.php
@@ -111,7 +111,7 @@ class QRImagick extends QROutputAbstract{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null):string|Imagick{
+	public function dump(string|null $file = null):string|Imagick{
 		$this->setBgColor();
 
 		$this->imagick = $this->createImage();
diff --git a/src/Output/QRInterventionImage.php b/src/Output/QRInterventionImage.php
index 298ff655b..c2b7a31c3 100644
--- a/src/Output/QRInterventionImage.php
+++ b/src/Output/QRInterventionImage.php
@@ -85,7 +85,7 @@ class QRInterventionImage extends QROutputAbstract{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null):string|ImageInterface{
+	public function dump(string|null $file = null):string|ImageInterface{
 		[$width, $height] = $this->getOutputDimensions();
 
 		$this->image = $this->manager->create($width, $height);
diff --git a/src/Output/QRMarkup.php b/src/Output/QRMarkup.php
index e7cce5f88..983f22b09 100644
--- a/src/Output/QRMarkup.php
+++ b/src/Output/QRMarkup.php
@@ -19,7 +19,7 @@ abstract class QRMarkup extends QROutputAbstract{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null):string{
+	public function dump(string|null $file = null):string{
 		$saveToFile = $file !== null;
 		$data       = $this->createMarkup($saveToFile);
 
diff --git a/src/Output/QROutputAbstract.php b/src/Output/QROutputAbstract.php
index 14489b436..9d1224958 100644
--- a/src/Output/QROutputAbstract.php
+++ b/src/Output/QROutputAbstract.php
@@ -180,7 +180,7 @@ abstract class QROutputAbstract implements QROutputInterface{
 	/**
 	 * Returns a base64 data URI for the given string and mime type
 	 */
-	protected function toBase64DataURI(string $data, string $mime = null):string{
+	protected function toBase64DataURI(string $data, string|null $mime = null):string{
 		return sprintf('data:%s;base64,%s', ($mime ?? static::MIME_TYPE), base64_encode($data));
 	}
 
@@ -192,7 +192,7 @@ abstract class QROutputAbstract implements QROutputInterface{
 	 *
 	 * @throws \chillerlan\QRCode\Output\QRCodeOutputException
 	 */
-	protected function saveToFile(string $data, string $file = null):void{
+	protected function saveToFile(string $data, string|null $file = null):void{
 
 		if($file === null){
 			return;
diff --git a/src/Output/QROutputInterface.php b/src/Output/QROutputInterface.php
index 8ef4d7928..b262157d0 100644
--- a/src/Output/QROutputInterface.php
+++ b/src/Output/QROutputInterface.php
@@ -129,6 +129,6 @@ interface QROutputInterface{
 	 *
 	 * @see \chillerlan\QRCode\QRCode::renderMatrix()
 	 */
-	public function dump(string $file = null):mixed;
+	public function dump(string|null $file = null):mixed;
 
 }
diff --git a/src/Output/QRStringJSON.php b/src/Output/QRStringJSON.php
index 3182129d4..05e580bb6 100644
--- a/src/Output/QRStringJSON.php
+++ b/src/Output/QRStringJSON.php
@@ -34,7 +34,7 @@ class QRStringJSON extends QROutputAbstract{
 	 * @inheritDoc
 	 * @throws \JsonException
 	 */
-	public function dump(string $file = null):string{
+	public function dump(string|null $file = null):string{
 		[$width, $height] = $this->getOutputDimensions();
 		$version   = $this->matrix->getVersion();
 		$dimension = $version->getDimension();
diff --git a/src/Output/QRStringText.php b/src/Output/QRStringText.php
index 309f123fc..594e1d841 100644
--- a/src/Output/QRStringText.php
+++ b/src/Output/QRStringText.php
@@ -43,7 +43,7 @@ class QRStringText extends QROutputAbstract{
 	/**
 	 * @inheritDoc
 	 */
-	public function dump(string $file = null):string{
+	public function dump(string|null $file = null):string{
 		$lines     = [];
 		$linestart = $this->options->textLineStart;
 
@@ -66,7 +66,7 @@ class QRStringText extends QROutputAbstract{
 	 *
 	 * @codeCoverageIgnore
 	 */
-	public static function ansi8(string $str, int $color, bool $background = null):string{
+	public static function ansi8(string $str, int $color, bool|null $background = null):string{
 		$color      = max(0, min($color, 255));
 		$background = ($background === true) ? 48 : 38;
 
diff --git a/src/QRCode.php b/src/QRCode.php
index 5140cfe46..dc54558bc 100755
--- a/src/QRCode.php
+++ b/src/QRCode.php
@@ -77,7 +77,7 @@ class QRCode{
 	/**
 	 * Renders a QR Code for the given $data and QROptions, saves $file optionally
 	 */
-	public function render(string $data = null, string $file = null):mixed{
+	public function render(string|null $data = null, string|null $file = null):mixed{
 
 		if($data !== null){
 			/** @var \chillerlan\QRCode\Data\QRDataModeInterface $dataInterface */
@@ -97,7 +97,7 @@ class QRCode{
 	/**
 	 * Renders a QR Code for the given QRMatrix and QROptions, saves $file optionally
 	 */
-	public function renderMatrix(QRMatrix $matrix, string $file = null):mixed{
+	public function renderMatrix(QRMatrix $matrix, string|null $file = null):mixed{
 		return $this->initOutputInterface($matrix)->dump($file ?? $this->options->cachefile);
 	}
 
diff --git a/src/QROptionsTrait.php b/src/QROptionsTrait.php
index 6a50b7671..49a8b05b2 100644
--- a/src/QROptionsTrait.php
+++ b/src/QROptionsTrait.php
@@ -125,7 +125,7 @@ trait QROptionsTrait{
 	 * @see \chillerlan\QRCode\QRCode::render()
 	 * @see \chillerlan\QRCode\QRCode::renderMatrix()
 	 */
-	protected ?string $cachefile = null;
+	protected string|null $cachefile = null;
 
 	/**
 	 * Toggle base64 data URI or raw data output (if applicable)
@@ -249,24 +249,24 @@ trait QROptionsTrait{
 	 *
 	 * if only `QROptions::$logoSpaceWidth` is given, the logo space is assumed a square of that size
 	 */
-	protected ?int $logoSpaceWidth = null;
+	protected int|null $logoSpaceWidth = null;
 
 	/**
 	 * Height of the logo space
 	 *
 	 * if only `QROptions::$logoSpaceHeight` is given, the logo space is assumed a square of that size
 	 */
-	protected ?int $logoSpaceHeight = null;
+	protected int|null $logoSpaceHeight = null;
 
 	/**
 	 * Optional horizontal start position of the logo space (top left corner)
 	 */
-	protected ?int $logoSpaceStartX = null;
+	protected int|null $logoSpaceStartX = null;
 
 	/**
 	 * Optional vertical start position of the logo space (top left corner)
 	 */
-	protected ?int $logoSpaceStartY = null;
+	protected int|null $logoSpaceStartY = null;
 
 
 	/*
@@ -431,7 +431,7 @@ trait QROptionsTrait{
 	 *
 	 * @see https://developer.mozilla.org/en-US/docs/Web/XSLT
 	 */
-	protected ?string $xmlStylesheet = null;
+	protected string|null $xmlStylesheet = null;
 
 
 	/**
@@ -517,7 +517,7 @@ trait QROptionsTrait{
 	/**
 	 * clamp the logo space values between 0 and maximum length (177 modules at version 40)
 	 */
-	protected function clampLogoSpaceValue(?int $value):?int{
+	protected function clampLogoSpaceValue(int|null $value):int|null{
 
 		if($value === null){
 			return null;
@@ -529,28 +529,28 @@ trait QROptionsTrait{
 	/**
 	 * clamp/set logo space width
 	 */
-	protected function set_logoSpaceWidth(?int $value):void{
+	protected function set_logoSpaceWidth(int|null $value):void{
 		$this->logoSpaceWidth = $this->clampLogoSpaceValue($value);
 	}
 
 	/**
 	 * clamp/set logo space height
 	 */
-	protected function set_logoSpaceHeight(?int $value):void{
+	protected function set_logoSpaceHeight(int|null $value):void{
 		$this->logoSpaceHeight = $this->clampLogoSpaceValue($value);
 	}
 
 	/**
 	 * clamp/set horizontal logo space start
 	 */
-	protected function set_logoSpaceStartX(?int $value):void{
+	protected function set_logoSpaceStartX(int|null $value):void{
 		$this->logoSpaceStartX = $this->clampLogoSpaceValue($value);
 	}
 
 	/**
 	 * clamp/set vertical logo space start
 	 */
-	protected function set_logoSpaceStartY(?int $value):void{
+	protected function set_logoSpaceStartY(int|null $value):void{
 		$this->logoSpaceStartY = $this->clampLogoSpaceValue($value);
 	}
 
diff --git a/tests/Common/ECICharsetTest.php b/tests/Common/ECICharsetTest.php
index 6046c093e..726102ae7 100644
--- a/tests/Common/ECICharsetTest.php
+++ b/tests/Common/ECICharsetTest.php
@@ -40,7 +40,7 @@ final class ECICharsetTest extends TestCase{
 	}
 
 	#[DataProvider('encodingProvider')]
-	public function testGetName(int $id, string $name = null):void{
+	public function testGetName(int $id, string|null $name = null):void{
 		$eciCharset = new ECICharset($id);
 
 		$this::assertSame($id, $eciCharset->getID());