diff --git a/.circleci/config.yml b/.circleci/config.yml
index 602d095..b3f6528 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -143,7 +143,7 @@ jobs:
             tag: << parameters.version >>
         parameters:
             version:
-                default: "7.4"
+                default: "8.3"
                 description: The `cimg/php` Docker image version tag.
                 type: string
             install-flags:
@@ -154,7 +154,7 @@ jobs:
             - when:
                   condition:
                       and:
-                          - equal: [ "8.1", <<parameters.version>> ]
+                          - equal: [ "8.3", <<parameters.version>> ]
                           - equal: [ "", <<parameters.install-flags>> ]
                   steps:
                       - run-phpunit-tests:
@@ -164,7 +164,7 @@ jobs:
                   condition:
                       not:
                           and:
-                              - equal: [ "8.1", <<parameters.version>> ]
+                              - equal: [ "8.3", <<parameters.version>> ]
                               - equal: [ "", <<parameters.install-flags>> ]
                   steps:
                       - run-phpunit-tests:
@@ -176,5 +176,5 @@ workflows:
             - matrix-conditions:
                   matrix:
                       parameters:
-                          version: ["7.4", "8.0", "8.1", "8.2"]
+                          version: ["7.4", "8.0", "8.1", "8.2", "8.3"]
                           install-flags: ["", "--prefer-lowest"]
diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..d9d308c
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,14 @@
+# This is the top-most .editorconfig file; do not search in parent directories.
+root = true
+
+# All files.
+[*]
+end_of_line = LF
+indent_style = space
+indent_size = 4
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[composer.{json,lock}]
+indent_size = 4
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..ac10f2a
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,16 @@
+# Exclude build/test files from archive
+/.circleci        export-ignore
+/test             export-ignore
+/.editorconfig    export-ignore
+/.gitattributes   export-ignore
+/.gitignore       export-ignore
+/docs             export-ignore
+/Doxyfile         export-ignore
+/doxygen.tag.xml  export-ignore
+/DoxygenLayout.xml export-ignore
+/phpcs.xml        export-ignore
+/phpunit.xml      export-ignore
+/rector.php       export-ignore
+
+# Configure diff output for .php and .phar files.
+*.php diff=php
diff --git a/.gitignore b/.gitignore
index e820736..fb48345 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,8 @@
 /vendor/
-.*
+.DS_Store
+.ddev
+.idea
+.phpunit.result.cache
 composer.lock
 html
 !.circleci
diff --git a/composer.json b/composer.json
index 01cb8d0..360c216 100644
--- a/composer.json
+++ b/composer.json
@@ -10,14 +10,15 @@
         }
     ],
     "require": {
-        "php": ">7.3 <8.3",
+        "php": ">7.3 <8.4",
         "ext-json": "*",
-        "getdkan/contracts": "^1.0.0"
+        "getdkan/contracts": "^1.1.3"
     },
     "require-dev": {
         "phpunit/phpunit": ">8.5.14 <10.0.0",
-        "rector/rector": "^0.15.17",
-        "squizlabs/php_codesniffer": "^3.7"
+        "rector/rector": "@stable",
+        "squizlabs/php_codesniffer": "^3.7",
+        "symfony/phpunit-bridge": "^7.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/phpunit.xml b/phpunit.xml
index 91698f0..1e1245d 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,11 +1,19 @@
 <?xml version="1.0"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd" verbose="false">
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.6/phpunit.xsd"
+         colors="true">
     <coverage processUncoveredFiles="true">
         <include>
-            <directory suffix=".php">src</directory>
+            <directory>src</directory>
         </include>
     </coverage>
+    <listeners>
+        <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener"/>
+    </listeners>
+    <php>
+        <!-- Don't fail for external dependencies. -->
+        <env name="SYMFONY_DEPRECATIONS_HELPER" value="max[self]=0"/>
+    </php>
     <testsuites>
         <testsuite name="all">
             <directory>test</directory>
diff --git a/rector.php b/rector.php
index 5b8d159..54fd922 100644
--- a/rector.php
+++ b/rector.php
@@ -8,8 +8,6 @@
 use Rector\DeadCode\Rector\ClassMethod\RemoveUselessParamTagRector;
 use Rector\DeadCode\Rector\ClassMethod\RemoveUselessReturnTagRector;
 use Rector\DeadCode\Rector\Property\RemoveUselessVarTagRector;
-use Rector\Core\ValueObject\PhpVersion;
-use Rector\Set\ValueObject\LevelSetList;
 
 return static function (RectorConfig $rectorConfig): void {
     $rectorConfig->paths([
@@ -17,17 +15,8 @@
         __DIR__ . '/test',
     ]);
 
-    // Our base version of PHP.
-    $rectorConfig->phpVersion(PhpVersion::PHP_74);
-
     $rectorConfig->sets([
-        // Interestingly, LevelSetList::UP_TO_PHP_82 does not preserve PHP 7.4,
-        // so we have to specify all the PHP versions leading up to it if we
-        // want to keep 7.4 idioms.
         SetList::PHP_74,
-        SetList::PHP_80,
-        SetList::PHP_81,
-        SetList::PHP_82,
         // Please no dead code or unneeded variables.
         SetList::DEAD_CODE,
         // Try to figure out type hints.
@@ -44,6 +33,7 @@
         RemoveUselessVarTagRector::class,
     ]);
 
+    $rectorConfig->removeUnusedImports();
     $rectorConfig->importNames();
     $rectorConfig->importShortClasses(false);
 };
diff --git a/src/Job/Job.php b/src/Job/Job.php
index a5480a0..a1c424b 100644
--- a/src/Job/Job.php
+++ b/src/Job/Job.php
@@ -55,7 +55,7 @@ public function run(): Result
         return $this->result;
     }
 
-    private function processDataFromRunIt($data)
+    private function processDataFromRunIt($data): void
     {
         if ($data instanceof Result) {
             $this->result = $data;
@@ -114,6 +114,9 @@ public function getResult(): Result
         return $this->result;
     }
 
+    /**
+     * @return mixed
+     */
     #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
diff --git a/src/Result.php b/src/Result.php
index 48e2c94..565fde6 100644
--- a/src/Result.php
+++ b/src/Result.php
@@ -18,7 +18,7 @@ class Result implements HydratableInterface
     private string $data = "";
     private string $error = "";
 
-    public function setStatus($status)
+    public function setStatus($status): void
     {
         $statuss = [self::WAITING, self::STOPPED, self::IN_PROGRESS, self::ERROR, self::DONE];
         if (in_array($status, $statuss)) {
@@ -53,6 +53,9 @@ public function getError(): string
         return $this->error;
     }
 
+    /**
+     * @return mixed
+     */
     #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {