diff --git a/examples/authenticator.php b/examples/authenticator.php
index a14ecf42e..2133be81f 100644
--- a/examples/authenticator.php
+++ b/examples/authenticator.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\Authenticator\{Authenticator, AuthenticatorOptionsTrait};
 use chillerlan\Authenticator\Authenticators\AuthenticatorInterface;
diff --git a/examples/custom_output.php b/examples/custom_output.php
index 02d453778..89a3dbb91 100644
--- a/examples/custom_output.php
+++ b/examples/custom_output.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpIllegalPsrClassPathInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Output\QROutputAbstract;
diff --git a/examples/eps.php b/examples/eps.php
index a15d17152..422d86f78 100644
--- a/examples/eps.php
+++ b/examples/eps.php
@@ -7,6 +7,7 @@
  * @copyright    2022 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/fpdf.php b/examples/fpdf.php
index f039f5828..cb40d4e22 100644
--- a/examples/fpdf.php
+++ b/examples/fpdf.php
@@ -6,6 +6,7 @@
  * @author       Maximilian Kresse
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/html.php b/examples/html.php
index c381e331d..4d5d95b07 100644
--- a/examples/html.php
+++ b/examples/html.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/image.php b/examples/image.php
index 428437347..662aeee32 100644
--- a/examples/image.php
+++ b/examples/image.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/imageWithLogo.php b/examples/imageWithLogo.php
index 6aa92a1d3..011a48627 100644
--- a/examples/imageWithLogo.php
+++ b/examples/imageWithLogo.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection, PhpIllegalPsrClassPathInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/imageWithRoundedShapes.php b/examples/imageWithRoundedShapes.php
index 5e349b207..a5434a75e 100644
--- a/examples/imageWithRoundedShapes.php
+++ b/examples/imageWithRoundedShapes.php
@@ -12,6 +12,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/imageWithText.php b/examples/imageWithText.php
index d80ea8f1f..b81e305de 100644
--- a/examples/imageWithText.php
+++ b/examples/imageWithText.php
@@ -11,6 +11,7 @@
  *
  * @noinspection PhpIllegalPsrClassPathInspection, PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Output\QRGdImagePNG;
diff --git a/examples/imagick.php b/examples/imagick.php
index 8a00960b6..65d31a1f5 100644
--- a/examples/imagick.php
+++ b/examples/imagick.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/imagickConvertSVGtoPNG.php b/examples/imagickConvertSVGtoPNG.php
index fa63568bc..5eab1f8c9 100644
--- a/examples/imagickConvertSVGtoPNG.php
+++ b/examples/imagickConvertSVGtoPNG.php
@@ -17,6 +17,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/imagickImageAsBackground.php b/examples/imagickImageAsBackground.php
index 815e1d048..c49915e62 100644
--- a/examples/imagickImageAsBackground.php
+++ b/examples/imagickImageAsBackground.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QRCodeException, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/imagickWithLogo.php b/examples/imagickWithLogo.php
index be6cf89e6..d6c19400a 100644
--- a/examples/imagickWithLogo.php
+++ b/examples/imagickWithLogo.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QRCodeException, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/intervention-image.php b/examples/intervention-image.php
index 33e863f2f..e09706556 100644
--- a/examples/intervention-image.php
+++ b/examples/intervention-image.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\Data\QRMatrix;
 use chillerlan\QRCode\Output\QRInterventionImage;
diff --git a/examples/multimode.php b/examples/multimode.php
index f7e9d1d38..cda9eda06 100644
--- a/examples/multimode.php
+++ b/examples/multimode.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 
diff --git a/examples/qrcode-interactive.php b/examples/qrcode-interactive.php
index 1173513ea..29fc8fc63 100644
--- a/examples/qrcode-interactive.php
+++ b/examples/qrcode-interactive.php
@@ -7,6 +7,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/reader.php b/examples/reader.php
index 6a2f1073a..0986beb82 100644
--- a/examples/reader.php
+++ b/examples/reader.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 
diff --git a/examples/reflectance.php b/examples/reflectance.php
index fe7878258..c581013a6 100644
--- a/examples/reflectance.php
+++ b/examples/reflectance.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/svg.php b/examples/svg.php
index a04863515..0c65fd7ca 100644
--- a/examples/svg.php
+++ b/examples/svg.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/svgConvertViaCanvas.php b/examples/svgConvertViaCanvas.php
index 830cfa743..4155a0dcb 100644
--- a/examples/svgConvertViaCanvas.php
+++ b/examples/svgConvertViaCanvas.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/svgMeltedModules.php b/examples/svgMeltedModules.php
index 7db76b3c8..200a38a1a 100644
--- a/examples/svgMeltedModules.php
+++ b/examples/svgMeltedModules.php
@@ -9,6 +9,7 @@
  * @see https://github.com/chillerlan/php-qrcode/issues/127
  * @see ./shapes.svg
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/svgRandomColoredDots.php b/examples/svgRandomColoredDots.php
index 5c86fdbe0..4b9f22288 100644
--- a/examples/svgRandomColoredDots.php
+++ b/examples/svgRandomColoredDots.php
@@ -11,6 +11,7 @@
  *
  * @noinspection PhpIllegalPsrClassPathInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/svgRoundQuietzone.php b/examples/svgRoundQuietzone.php
index 05407ca6f..649079480 100644
--- a/examples/svgRoundQuietzone.php
+++ b/examples/svgRoundQuietzone.php
@@ -11,6 +11,7 @@
  *
  * @noinspection PhpIllegalPsrClassPathInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QRCodeException, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/svgWithLogo.php b/examples/svgWithLogo.php
index bf0750ff2..82bba4a19 100644
--- a/examples/svgWithLogo.php
+++ b/examples/svgWithLogo.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QRCodeException, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/svgWithLogoAndCustomShapes.php b/examples/svgWithLogoAndCustomShapes.php
index 2298ded20..99eb1676a 100644
--- a/examples/svgWithLogoAndCustomShapes.php
+++ b/examples/svgWithLogoAndCustomShapes.php
@@ -11,6 +11,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QRCodeException, QROptions};
 use chillerlan\QRCode\Common\EccLevel;
diff --git a/examples/text.php b/examples/text.php
index 1aa83ec88..7645a2c8b 100644
--- a/examples/text.php
+++ b/examples/text.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\{QRCode, QROptions};
 use chillerlan\QRCode\Data\QRMatrix;
diff --git a/examples/xml.php b/examples/xml.php
index ad6a9a527..e8afcd74c 100644
--- a/examples/xml.php
+++ b/examples/xml.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 use chillerlan\QRCode\Data\QRMatrix;
 use chillerlan\QRCode\{QRCode, QROptions};
diff --git a/phpcs.xml.dist b/phpcs.xml.dist
index b7dbe05c3..38624bc4f 100644
--- a/phpcs.xml.dist
+++ b/phpcs.xml.dist
@@ -74,7 +74,6 @@
 
 	<rule ref="SlevomatCodingStandard.Strings.DisallowVariableParsing"/>
 
-	<!--<rule ref="SlevomatCodingStandard.TypeHints.DeclareStrictTypes"/>-->
 	<!--<rule ref="SlevomatCodingStandard.TypeHints.DisallowMixedTypeHint"/>-->
 	<rule ref="SlevomatCodingStandard.TypeHints.LongTypeHints"/>
 	<rule ref="SlevomatCodingStandard.TypeHints.NullTypeHintOnLastPosition"/>
@@ -87,6 +86,13 @@
 	<rule ref="SlevomatCodingStandard.Variables.DuplicateAssignmentToVariable"/>
 	<rule ref="SlevomatCodingStandard.Variables.UselessVariable"/>
 
+	<rule ref="SlevomatCodingStandard.TypeHints.DeclareStrictTypes">
+		<properties>
+			<property name="linesCountBeforeDeclare" value="0"/>
+			<property name="linesCountAfterDeclare" value="1"/>
+			<property name="spacesCountAroundEqualsSign" value="0"/>
+		</properties>
+	</rule>
 
 	<rule ref="SlevomatCodingStandard.Functions.RequireMultiLineCall">
 		<properties>
@@ -147,7 +153,7 @@
 	<rule ref="Generic.PHP.LowerCaseKeyword"/>
 	<rule ref="Generic.PHP.LowerCaseType"/>
 	<rule ref="Generic.PHP.NoSilencedErrors"/>
-	<!--<rule ref="Generic.PHP.RequireStrictTypes"/>-->
+	<rule ref="Generic.PHP.RequireStrictTypes"/>
 	<rule ref="Generic.PHP.SAPIUsage"/>
 	<rule ref="Generic.PHP.Syntax"/>
 	<rule ref="Generic.Strings.UnnecessaryStringConcat"/>
diff --git a/src/Common/BitBuffer.php b/src/Common/BitBuffer.php
index d6be3fe9c..480340b99 100644
--- a/src/Common/BitBuffer.php
+++ b/src/Common/BitBuffer.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/ECICharset.php b/src/Common/ECICharset.php
index 09f90c19a..d6f78b743 100644
--- a/src/Common/ECICharset.php
+++ b/src/Common/ECICharset.php
@@ -8,6 +8,7 @@
  * @copyright    2021 smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/EccLevel.php b/src/Common/EccLevel.php
index 9aa349f33..ae7720433 100644
--- a/src/Common/EccLevel.php
+++ b/src/Common/EccLevel.php
@@ -7,6 +7,7 @@
  * @copyright    2020 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/GDLuminanceSource.php b/src/Common/GDLuminanceSource.php
index 32f6be051..e7b60d800 100644
--- a/src/Common/GDLuminanceSource.php
+++ b/src/Common/GDLuminanceSource.php
@@ -10,6 +10,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/GF256.php b/src/Common/GF256.php
index d8ba0950b..f3e4fd5ee 100644
--- a/src/Common/GF256.php
+++ b/src/Common/GF256.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/GenericGFPoly.php b/src/Common/GenericGFPoly.php
index da1fcaefc..5f8160958 100644
--- a/src/Common/GenericGFPoly.php
+++ b/src/Common/GenericGFPoly.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/IMagickLuminanceSource.php b/src/Common/IMagickLuminanceSource.php
index 1e1b01b08..d528cb3e8 100644
--- a/src/Common/IMagickLuminanceSource.php
+++ b/src/Common/IMagickLuminanceSource.php
@@ -10,6 +10,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/LuminanceSourceAbstract.php b/src/Common/LuminanceSourceAbstract.php
index e92507b2a..b4c55014f 100644
--- a/src/Common/LuminanceSourceAbstract.php
+++ b/src/Common/LuminanceSourceAbstract.php
@@ -9,6 +9,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/LuminanceSourceInterface.php b/src/Common/LuminanceSourceInterface.php
index 209b52af0..621d85924 100644
--- a/src/Common/LuminanceSourceInterface.php
+++ b/src/Common/LuminanceSourceInterface.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/MaskPattern.php b/src/Common/MaskPattern.php
index 5455310b3..e22d5511a 100644
--- a/src/Common/MaskPattern.php
+++ b/src/Common/MaskPattern.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/Mode.php b/src/Common/Mode.php
index 461cea307..a3b1f8f38 100644
--- a/src/Common/Mode.php
+++ b/src/Common/Mode.php
@@ -7,6 +7,7 @@
  * @copyright    2020 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Common/Version.php b/src/Common/Version.php
index 15a4d4a9b..7c5938527 100644
--- a/src/Common/Version.php
+++ b/src/Common/Version.php
@@ -7,6 +7,7 @@
  * @copyright    2020 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Common;
 
diff --git a/src/Data/AlphaNum.php b/src/Data/AlphaNum.php
index 4cfc9fb9d..882c1f7ea 100644
--- a/src/Data/AlphaNum.php
+++ b/src/Data/AlphaNum.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/Byte.php b/src/Data/Byte.php
index 7896530d0..00f611d40 100644
--- a/src/Data/Byte.php
+++ b/src/Data/Byte.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/ECI.php b/src/Data/ECI.php
index bd4916ed6..c1d4021f5 100644
--- a/src/Data/ECI.php
+++ b/src/Data/ECI.php
@@ -7,6 +7,7 @@
  * @copyright    2020 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/Hanzi.php b/src/Data/Hanzi.php
index 5c469187c..00cf03708 100644
--- a/src/Data/Hanzi.php
+++ b/src/Data/Hanzi.php
@@ -7,6 +7,7 @@
  * @copyright    2020 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/Kanji.php b/src/Data/Kanji.php
index e27b65a36..37450f850 100644
--- a/src/Data/Kanji.php
+++ b/src/Data/Kanji.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/Number.php b/src/Data/Number.php
index 4943ce9fb..a776bbd73 100644
--- a/src/Data/Number.php
+++ b/src/Data/Number.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/QRCodeDataException.php b/src/Data/QRCodeDataException.php
index 04ffbd7ed..df55cc56e 100644
--- a/src/Data/QRCodeDataException.php
+++ b/src/Data/QRCodeDataException.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/QRData.php b/src/Data/QRData.php
index 4386ae22a..65e46c5b7 100644
--- a/src/Data/QRData.php
+++ b/src/Data/QRData.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/QRDataModeAbstract.php b/src/Data/QRDataModeAbstract.php
index 2a8b9d00c..560d631a9 100644
--- a/src/Data/QRDataModeAbstract.php
+++ b/src/Data/QRDataModeAbstract.php
@@ -7,6 +7,7 @@
  * @copyright    2020 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/QRDataModeInterface.php b/src/Data/QRDataModeInterface.php
index fcd333628..f553a90ac 100644
--- a/src/Data/QRDataModeInterface.php
+++ b/src/Data/QRDataModeInterface.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/QRMatrix.php b/src/Data/QRMatrix.php
index ead50dddf..2ebda54af 100755
--- a/src/Data/QRMatrix.php
+++ b/src/Data/QRMatrix.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Data/ReedSolomonEncoder.php b/src/Data/ReedSolomonEncoder.php
index f5c42c0a7..bf7fc687d 100644
--- a/src/Data/ReedSolomonEncoder.php
+++ b/src/Data/ReedSolomonEncoder.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Data;
 
diff --git a/src/Decoder/Binarizer.php b/src/Decoder/Binarizer.php
index 54475734e..c035cdded 100644
--- a/src/Decoder/Binarizer.php
+++ b/src/Decoder/Binarizer.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Decoder;
 
diff --git a/src/Decoder/BitMatrix.php b/src/Decoder/BitMatrix.php
index 97690e6dc..455a55aae 100644
--- a/src/Decoder/BitMatrix.php
+++ b/src/Decoder/BitMatrix.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Decoder;
 
diff --git a/src/Decoder/Decoder.php b/src/Decoder/Decoder.php
index a2f8767b3..0fab160b9 100644
--- a/src/Decoder/Decoder.php
+++ b/src/Decoder/Decoder.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Decoder;
 
diff --git a/src/Decoder/DecoderResult.php b/src/Decoder/DecoderResult.php
index da2ced8a9..c79e134d3 100644
--- a/src/Decoder/DecoderResult.php
+++ b/src/Decoder/DecoderResult.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Decoder;
 
diff --git a/src/Decoder/QRCodeDecoderException.php b/src/Decoder/QRCodeDecoderException.php
index 11157afc1..4be3a5cd3 100644
--- a/src/Decoder/QRCodeDecoderException.php
+++ b/src/Decoder/QRCodeDecoderException.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Decoder;
 
diff --git a/src/Decoder/ReedSolomonDecoder.php b/src/Decoder/ReedSolomonDecoder.php
index 0b5eb5860..3b9e668dd 100644
--- a/src/Decoder/ReedSolomonDecoder.php
+++ b/src/Decoder/ReedSolomonDecoder.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Decoder;
 
diff --git a/src/Detector/AlignmentPattern.php b/src/Detector/AlignmentPattern.php
index d3a1282cf..2cef78889 100644
--- a/src/Detector/AlignmentPattern.php
+++ b/src/Detector/AlignmentPattern.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/AlignmentPatternFinder.php b/src/Detector/AlignmentPatternFinder.php
index 917394845..7c2b09049 100644
--- a/src/Detector/AlignmentPatternFinder.php
+++ b/src/Detector/AlignmentPatternFinder.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/Detector.php b/src/Detector/Detector.php
index e3188d0e4..d8473f6cc 100644
--- a/src/Detector/Detector.php
+++ b/src/Detector/Detector.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/FinderPattern.php b/src/Detector/FinderPattern.php
index bc55b999e..ba4a6dde7 100644
--- a/src/Detector/FinderPattern.php
+++ b/src/Detector/FinderPattern.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/FinderPatternFinder.php b/src/Detector/FinderPatternFinder.php
index baed34ada..8dfb197bd 100644
--- a/src/Detector/FinderPatternFinder.php
+++ b/src/Detector/FinderPatternFinder.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/GridSampler.php b/src/Detector/GridSampler.php
index 093a112ac..ac7764405 100644
--- a/src/Detector/GridSampler.php
+++ b/src/Detector/GridSampler.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/PerspectiveTransform.php b/src/Detector/PerspectiveTransform.php
index 31a83272d..351f3c75f 100644
--- a/src/Detector/PerspectiveTransform.php
+++ b/src/Detector/PerspectiveTransform.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/QRCodeDetectorException.php b/src/Detector/QRCodeDetectorException.php
index 2444e193c..550144a31 100644
--- a/src/Detector/QRCodeDetectorException.php
+++ b/src/Detector/QRCodeDetectorException.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Detector/ResultPoint.php b/src/Detector/ResultPoint.php
index 34b64812e..8f3432a88 100644
--- a/src/Detector/ResultPoint.php
+++ b/src/Detector/ResultPoint.php
@@ -8,6 +8,7 @@
  * @copyright    2021 Smiley
  * @license      Apache-2.0
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Detector;
 
diff --git a/src/Output/CssColorModuleValueTrait.php b/src/Output/CssColorModuleValueTrait.php
index a6514ad5c..cba31f096 100644
--- a/src/Output/CssColorModuleValueTrait.php
+++ b/src/Output/CssColorModuleValueTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRCodeOutputException.php b/src/Output/QRCodeOutputException.php
index bf30f1bb0..54c10c246 100644
--- a/src/Output/QRCodeOutputException.php
+++ b/src/Output/QRCodeOutputException.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QREps.php b/src/Output/QREps.php
index 457c0d468..1fadce385 100644
--- a/src/Output/QREps.php
+++ b/src/Output/QREps.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRFpdf.php b/src/Output/QRFpdf.php
index 7ccc94fa7..343103113 100644
--- a/src/Output/QRFpdf.php
+++ b/src/Output/QRFpdf.php
@@ -8,6 +8,7 @@
  *
  * @see https://github.com/chillerlan/php-qrcode/pull/49
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRGdImage.php b/src/Output/QRGdImage.php
index d7666e5eb..d7af0af84 100644
--- a/src/Output/QRGdImage.php
+++ b/src/Output/QRGdImage.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRGdImageAVIF.php b/src/Output/QRGdImageAVIF.php
index f9e256e97..067b3b5ca 100644
--- a/src/Output/QRGdImageAVIF.php
+++ b/src/Output/QRGdImageAVIF.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRGdImageBMP.php b/src/Output/QRGdImageBMP.php
index 0754c7b59..5b76ce86a 100644
--- a/src/Output/QRGdImageBMP.php
+++ b/src/Output/QRGdImageBMP.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRGdImageGIF.php b/src/Output/QRGdImageGIF.php
index 5c9202665..e15441692 100644
--- a/src/Output/QRGdImageGIF.php
+++ b/src/Output/QRGdImageGIF.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRGdImageJPEG.php b/src/Output/QRGdImageJPEG.php
index cbe40f09e..5152a8bb3 100644
--- a/src/Output/QRGdImageJPEG.php
+++ b/src/Output/QRGdImageJPEG.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRGdImagePNG.php b/src/Output/QRGdImagePNG.php
index 09de6ccbd..3343eddf6 100644
--- a/src/Output/QRGdImagePNG.php
+++ b/src/Output/QRGdImagePNG.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRGdImageWEBP.php b/src/Output/QRGdImageWEBP.php
index 9f63a4f2b..029be752d 100644
--- a/src/Output/QRGdImageWEBP.php
+++ b/src/Output/QRGdImageWEBP.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRImagick.php b/src/Output/QRImagick.php
index 73164cb1d..90396f2e9 100644
--- a/src/Output/QRImagick.php
+++ b/src/Output/QRImagick.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRInterventionImage.php b/src/Output/QRInterventionImage.php
index 806d270e4..b887d25b1 100644
--- a/src/Output/QRInterventionImage.php
+++ b/src/Output/QRInterventionImage.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRMarkup.php b/src/Output/QRMarkup.php
index d793aada3..fce200818 100644
--- a/src/Output/QRMarkup.php
+++ b/src/Output/QRMarkup.php
@@ -7,6 +7,7 @@
  * @copyright    2016 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRMarkupHTML.php b/src/Output/QRMarkupHTML.php
index d2416b896..f12e77886 100644
--- a/src/Output/QRMarkupHTML.php
+++ b/src/Output/QRMarkupHTML.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRMarkupSVG.php b/src/Output/QRMarkupSVG.php
index bbf9bb575..9d14cff7a 100644
--- a/src/Output/QRMarkupSVG.php
+++ b/src/Output/QRMarkupSVG.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRMarkupXML.php b/src/Output/QRMarkupXML.php
index b6fa4d89c..6d78a2a8e 100644
--- a/src/Output/QRMarkupXML.php
+++ b/src/Output/QRMarkupXML.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QROutputAbstract.php b/src/Output/QROutputAbstract.php
index 76f97288d..ab97e3b72 100644
--- a/src/Output/QROutputAbstract.php
+++ b/src/Output/QROutputAbstract.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QROutputInterface.php b/src/Output/QROutputInterface.php
index b262157d0..44d68225b 100644
--- a/src/Output/QROutputInterface.php
+++ b/src/Output/QROutputInterface.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRStringJSON.php b/src/Output/QRStringJSON.php
index 2531d8fad..35d24ad60 100644
--- a/src/Output/QRStringJSON.php
+++ b/src/Output/QRStringJSON.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/QRStringText.php b/src/Output/QRStringText.php
index 1a7f15645..2bf8f5ab1 100644
--- a/src/Output/QRStringText.php
+++ b/src/Output/QRStringText.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/Output/RGBArrayModuleValueTrait.php b/src/Output/RGBArrayModuleValueTrait.php
index 9c0138f74..0703f16da 100644
--- a/src/Output/RGBArrayModuleValueTrait.php
+++ b/src/Output/RGBArrayModuleValueTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode\Output;
 
diff --git a/src/QRCode.php b/src/QRCode.php
index 777dbf052..318743ceb 100755
--- a/src/QRCode.php
+++ b/src/QRCode.php
@@ -9,6 +9,7 @@
  *
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode;
 
diff --git a/src/QRCodeException.php b/src/QRCodeException.php
index 600ce50ea..e1f86022d 100644
--- a/src/QRCodeException.php
+++ b/src/QRCodeException.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode;
 
diff --git a/src/QRCodeReaderOptionsTrait.php b/src/QRCodeReaderOptionsTrait.php
index b046b4984..18a3dc517 100644
--- a/src/QRCodeReaderOptionsTrait.php
+++ b/src/QRCodeReaderOptionsTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode;
 
diff --git a/src/QROptions.php b/src/QROptions.php
index 929877d0f..1ccf4f894 100644
--- a/src/QROptions.php
+++ b/src/QROptions.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode;
 
diff --git a/src/QROptionsTrait.php b/src/QROptionsTrait.php
index 4695ef286..85809cba3 100644
--- a/src/QROptionsTrait.php
+++ b/src/QROptionsTrait.php
@@ -11,6 +11,7 @@
  *
  * @noinspection PhpUnused, PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCode;
 
diff --git a/tests/BuildDirTrait.php b/tests/BuildDirTrait.php
index ca91be930..858b17731 100644
--- a/tests/BuildDirTrait.php
+++ b/tests/BuildDirTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;
 
diff --git a/tests/Common/BitBufferTest.php b/tests/Common/BitBufferTest.php
index e4ae40f8e..42931de5e 100644
--- a/tests/Common/BitBufferTest.php
+++ b/tests/Common/BitBufferTest.php
@@ -7,6 +7,7 @@
  * @copyright    2015 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Common;
 
diff --git a/tests/Common/ECICharsetTest.php b/tests/Common/ECICharsetTest.php
index c47c3cea0..058538e94 100644
--- a/tests/Common/ECICharsetTest.php
+++ b/tests/Common/ECICharsetTest.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Common;
 
diff --git a/tests/Common/EccLevelTest.php b/tests/Common/EccLevelTest.php
index 3ad207a90..a62c24bb9 100644
--- a/tests/Common/EccLevelTest.php
+++ b/tests/Common/EccLevelTest.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Common;
 
diff --git a/tests/Common/MaskPatternTest.php b/tests/Common/MaskPatternTest.php
index 0fc099ce1..31cbbb81f 100644
--- a/tests/Common/MaskPatternTest.php
+++ b/tests/Common/MaskPatternTest.php
@@ -10,6 +10,7 @@
  *
  * @codingStandardsIgnoreFile Squiz.Arrays.ArrayDeclaration.NoCommaAfterLast
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Common;
 
diff --git a/tests/Common/ModeTest.php b/tests/Common/ModeTest.php
index 7e533555a..7706f0c4b 100644
--- a/tests/Common/ModeTest.php
+++ b/tests/Common/ModeTest.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Common;
 
diff --git a/tests/Common/VersionTest.php b/tests/Common/VersionTest.php
index 2069ac66e..2c95a23b3 100644
--- a/tests/Common/VersionTest.php
+++ b/tests/Common/VersionTest.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Common;
 
diff --git a/tests/Data/AlphaNumTest.php b/tests/Data/AlphaNumTest.php
index 2050faa78..deeeb198f 100644
--- a/tests/Data/AlphaNumTest.php
+++ b/tests/Data/AlphaNumTest.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/ByteTest.php b/tests/Data/ByteTest.php
index 0a73b5e38..7d9c59dbf 100644
--- a/tests/Data/ByteTest.php
+++ b/tests/Data/ByteTest.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/DataInterfaceTestAbstract.php b/tests/Data/DataInterfaceTestAbstract.php
index 3b2b82357..d30a5e4b1 100644
--- a/tests/Data/DataInterfaceTestAbstract.php
+++ b/tests/Data/DataInterfaceTestAbstract.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/ECITest.php b/tests/Data/ECITest.php
index c19f4154c..c74677346 100644
--- a/tests/Data/ECITest.php
+++ b/tests/Data/ECITest.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/HanziTest.php b/tests/Data/HanziTest.php
index 267f06388..36ffe0b10 100644
--- a/tests/Data/HanziTest.php
+++ b/tests/Data/HanziTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/KanjiTest.php b/tests/Data/KanjiTest.php
index 886d2a622..8619c9e04 100644
--- a/tests/Data/KanjiTest.php
+++ b/tests/Data/KanjiTest.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/NumberTest.php b/tests/Data/NumberTest.php
index b48d39878..e80e57b61 100644
--- a/tests/Data/NumberTest.php
+++ b/tests/Data/NumberTest.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/QRDataTest.php b/tests/Data/QRDataTest.php
index 8594b3886..0e7fb7654 100644
--- a/tests/Data/QRDataTest.php
+++ b/tests/Data/QRDataTest.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Data/QRMatrixTest.php b/tests/Data/QRMatrixTest.php
index ff42b0611..036bcfcdc 100755
--- a/tests/Data/QRMatrixTest.php
+++ b/tests/Data/QRMatrixTest.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Data;
 
diff --git a/tests/Output/CssColorModuleValueProviderTrait.php b/tests/Output/CssColorModuleValueProviderTrait.php
index eae2dbea2..2b520103d 100644
--- a/tests/Output/CssColorModuleValueProviderTrait.php
+++ b/tests/Output/CssColorModuleValueProviderTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QREpsTest.php b/tests/Output/QREpsTest.php
index 56b6dca63..03dca73de 100644
--- a/tests/Output/QREpsTest.php
+++ b/tests/Output/QREpsTest.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRFpdfTest.php b/tests/Output/QRFpdfTest.php
index 0e34cb505..390c22792 100644
--- a/tests/Output/QRFpdfTest.php
+++ b/tests/Output/QRFpdfTest.php
@@ -7,6 +7,7 @@
  * @copyright    2020 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRGdImageAVIFTest.php b/tests/Output/QRGdImageAVIFTest.php
index 568ee6c0f..f84149c56 100644
--- a/tests/Output/QRGdImageAVIFTest.php
+++ b/tests/Output/QRGdImageAVIFTest.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRGdImageBMPTest.php b/tests/Output/QRGdImageBMPTest.php
index 5e7044578..eba634d5b 100644
--- a/tests/Output/QRGdImageBMPTest.php
+++ b/tests/Output/QRGdImageBMPTest.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRGdImageGIFTest.php b/tests/Output/QRGdImageGIFTest.php
index 2dcf96f11..0f6bfc66d 100644
--- a/tests/Output/QRGdImageGIFTest.php
+++ b/tests/Output/QRGdImageGIFTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRGdImageJPGTest.php b/tests/Output/QRGdImageJPGTest.php
index 216a67f02..d7e19c8d3 100644
--- a/tests/Output/QRGdImageJPGTest.php
+++ b/tests/Output/QRGdImageJPGTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRGdImagePNGTest.php b/tests/Output/QRGdImagePNGTest.php
index 6443a5c35..a36622bd5 100644
--- a/tests/Output/QRGdImagePNGTest.php
+++ b/tests/Output/QRGdImagePNGTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRGdImageTestAbstract.php b/tests/Output/QRGdImageTestAbstract.php
index c5a740225..b59f09c9b 100644
--- a/tests/Output/QRGdImageTestAbstract.php
+++ b/tests/Output/QRGdImageTestAbstract.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRGdImageWEBPTest.php b/tests/Output/QRGdImageWEBPTest.php
index 4d18396fe..29433eca4 100644
--- a/tests/Output/QRGdImageWEBPTest.php
+++ b/tests/Output/QRGdImageWEBPTest.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRImagickTest.php b/tests/Output/QRImagickTest.php
index 397cca6cb..fa83b333a 100644
--- a/tests/Output/QRImagickTest.php
+++ b/tests/Output/QRImagickTest.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRInterventionImageTest.php b/tests/Output/QRInterventionImageTest.php
index 91e53865f..2c127c760 100644
--- a/tests/Output/QRInterventionImageTest.php
+++ b/tests/Output/QRInterventionImageTest.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRMarkupHTMLTest.php b/tests/Output/QRMarkupHTMLTest.php
index da47fa12a..1bac5bedb 100644
--- a/tests/Output/QRMarkupHTMLTest.php
+++ b/tests/Output/QRMarkupHTMLTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRMarkupSVGTest.php b/tests/Output/QRMarkupSVGTest.php
index 74d2d83a8..feebc0932 100644
--- a/tests/Output/QRMarkupSVGTest.php
+++ b/tests/Output/QRMarkupSVGTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRMarkupTestAbstract.php b/tests/Output/QRMarkupTestAbstract.php
index 0d908af99..44f2902e2 100644
--- a/tests/Output/QRMarkupTestAbstract.php
+++ b/tests/Output/QRMarkupTestAbstract.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRMarkupXMLTest.php b/tests/Output/QRMarkupXMLTest.php
index 843fae276..9e569bf9d 100644
--- a/tests/Output/QRMarkupXMLTest.php
+++ b/tests/Output/QRMarkupXMLTest.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QROutputTestAbstract.php b/tests/Output/QROutputTestAbstract.php
index 27367d2f2..5b3231bd1 100644
--- a/tests/Output/QROutputTestAbstract.php
+++ b/tests/Output/QROutputTestAbstract.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRStringJSONTest.php b/tests/Output/QRStringJSONTest.php
index ce28c94f5..59317d082 100644
--- a/tests/Output/QRStringJSONTest.php
+++ b/tests/Output/QRStringJSONTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/QRStringTextTest.php b/tests/Output/QRStringTextTest.php
index 08835ba2c..b145ab541 100644
--- a/tests/Output/QRStringTextTest.php
+++ b/tests/Output/QRStringTextTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/Output/RGBArrayModuleValueProviderTrait.php b/tests/Output/RGBArrayModuleValueProviderTrait.php
index f22e49bac..db703a6b5 100644
--- a/tests/Output/RGBArrayModuleValueProviderTrait.php
+++ b/tests/Output/RGBArrayModuleValueProviderTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2024 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest\Output;
 
diff --git a/tests/QRCodeReaderGDTest.php b/tests/QRCodeReaderGDTest.php
index 3b7039ab1..c2056634f 100644
--- a/tests/QRCodeReaderGDTest.php
+++ b/tests/QRCodeReaderGDTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;
 
diff --git a/tests/QRCodeReaderImagickTest.php b/tests/QRCodeReaderImagickTest.php
index ed21cbeea..31508a2e3 100644
--- a/tests/QRCodeReaderImagickTest.php
+++ b/tests/QRCodeReaderImagickTest.php
@@ -7,6 +7,7 @@
  * @copyright    2021 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;
 
diff --git a/tests/QRCodeReaderTestAbstract.php b/tests/QRCodeReaderTestAbstract.php
index db4541fcf..353cce661 100644
--- a/tests/QRCodeReaderTestAbstract.php
+++ b/tests/QRCodeReaderTestAbstract.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpComposerExtensionStubsInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;
 
diff --git a/tests/QRCodeTest.php b/tests/QRCodeTest.php
index 08c3b85a4..ff1c863e1 100755
--- a/tests/QRCodeTest.php
+++ b/tests/QRCodeTest.php
@@ -7,6 +7,7 @@
  * @copyright    2017 Smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;
 
diff --git a/tests/QRMatrixDebugTrait.php b/tests/QRMatrixDebugTrait.php
index 424c33c6d..041ce73dc 100644
--- a/tests/QRMatrixDebugTrait.php
+++ b/tests/QRMatrixDebugTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2023 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;
 
diff --git a/tests/QRMaxLengthTrait.php b/tests/QRMaxLengthTrait.php
index 59472ef85..f8bf10871 100644
--- a/tests/QRMaxLengthTrait.php
+++ b/tests/QRMaxLengthTrait.php
@@ -7,6 +7,7 @@
  * @copyright    2022 smiley
  * @license      MIT
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;
 
diff --git a/tests/QROptionsTest.php b/tests/QROptionsTest.php
index bfcde1614..bb47063b6 100644
--- a/tests/QROptionsTest.php
+++ b/tests/QROptionsTest.php
@@ -9,6 +9,7 @@
  *
  * @noinspection PhpUnusedLocalVariableInspection
  */
+declare(strict_types=1);
 
 namespace chillerlan\QRCodeTest;