diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4b1dddff..ca07d6bf 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -46,7 +46,7 @@ jobs:
       run: PHP_CS_FIXER_IGNORE_ENV=1 ./bin/php-cs-fixer fix --dry-run -v
 
     - name: Static Analysis
-      run: ./bin/psalm
+      run: ./bin/psalm.phar
 
     - name: Test
       run: ./bin/phpunit -d memory_limit=-1 --coverage-clover clover.xml
diff --git a/.gitignore b/.gitignore
index 87a73ec0..4e33d6de 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,7 +6,9 @@
 /web
 /bin/
 !/bin/box.phar
+!/bin/psalm.phar
 phparkitect.phar
 composer.lock
 .php-version
 composer.phar
+.phpunit.cache/
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 4246b65d..30928aea 100644
--- a/Makefile
+++ b/Makefile
@@ -36,7 +36,7 @@ csfix: ## it launches cs fix
 	bin/php-cs-fixer fix -v
 
 psalm: ## it launches psalm
-	bin/psalm
+	bin/psalm.phar
 
 build: ## it launches all the build
 	composer install
diff --git a/bin/psalm.phar b/bin/psalm.phar
new file mode 100755
index 00000000..24b9ae3e
Binary files /dev/null and b/bin/psalm.phar differ
diff --git a/composer.json b/composer.json
index b449d82a..c4df5fb5 100644
--- a/composer.json
+++ b/composer.json
@@ -37,7 +37,6 @@
     "require-dev": {
         "roave/security-advisories": "dev-master",
         "symfony/var-dumper": "^3.0|^4.0|^5.0|^6.0|^7.0",
-        "vimeo/psalm": "^4.6",
         "phpunit/phpunit": "^7.5|^9.0|^10.0",
         "mikey179/vfsstream": "^1.6",
         "phpspec/prophecy": "^1.10",
@@ -55,7 +54,8 @@
         }
     },
     "config": {
-        "bin-dir": "bin"
+        "bin-dir": "bin",
+        "sort-packages": true
     },
     "bin": [
         "bin-stub/phparkitect"
diff --git a/phpunit.xml b/phpunit.xml
index f388db62..f5bde5ef 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,21 +1,27 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/7.5/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.6/phpunit.xsd"
          bootstrap="vendor/autoload.php"
-         beStrictAboutCoversAnnotation="true"
+         cacheResultFile=".phpunit.cache/test-results"
+         executionOrder="depends,defects"
+         forceCoversAnnotation="false"
+         beStrictAboutCoversAnnotation="false"
          beStrictAboutOutputDuringTests="true"
          beStrictAboutTodoAnnotatedTests="true"
+         convertDeprecationsToExceptions="true"
+         failOnRisky="false"
+         failOnWarning="true"
          verbose="true">
-
     <testsuites>
         <testsuite name="default">
             <directory>tests</directory>
         </testsuite>
     </testsuites>
 
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
+    <coverage cacheDirectory=".phpunit.cache/code-coverage"
+              processUncoveredFiles="true">
+        <include>
             <directory suffix=".php">src</directory>
-        </whitelist>
-    </filter>
+        </include>
+    </coverage>
 </phpunit>
diff --git a/psalm.xml b/psalm.xml
index b6e24917..9c52fffc 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -4,7 +4,8 @@
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"
     xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
-
+    findUnusedCode="false"
+    findUnusedBaselineEntry="false"
     allowStringToStandInForClass="true"
 >
     <projectFiles>
diff --git a/src/Analyzer/ClassDescription.php b/src/Analyzer/ClassDescription.php
index 2f61ff50..e11beeba 100644
--- a/src/Analyzer/ClassDescription.php
+++ b/src/Analyzer/ClassDescription.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Arkitect\Analyzer;
@@ -46,6 +47,7 @@ class ClassDescription
      * @param list<FullyQualifiedClassName> $interfaces
      * @param ?FullyQualifiedClassName      $extends
      * @param list<FullyQualifiedClassName> $attributes
+     * @param list<string>                  $docBlock
      */
     public function __construct(
         FullyQualifiedClassName $FQCN,
diff --git a/src/Analyzer/FileVisitor.php b/src/Analyzer/FileVisitor.php
index 35195586..1d0af495 100644
--- a/src/Analyzer/FileVisitor.php
+++ b/src/Analyzer/FileVisitor.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Arkitect\Analyzer;
@@ -30,7 +31,7 @@ public function enterNode(Node $node): void
 
             foreach ($node->implements as $interface) {
                 $this->classDescriptionBuilder
-                     ->addInterface($interface->toString(), $interface->getLine());
+                    ->addInterface($interface->toString(), $interface->getLine());
             }
 
             if (!$node->isAnonymous() && null !== $node->extends) {
@@ -76,7 +77,8 @@ public function enterNode(Node $node): void
          *
          * @see FileVisitorTest::test_it_should_return_errors_for_const_outside_namespace
          */
-        if ($node instanceof Node\Expr\ClassConstFetch
+        if (
+            $node instanceof Node\Expr\ClassConstFetch
             && method_exists($node->class, 'toString')
         ) {
             if ($this->isSelfOrStaticOrParent($node->class->toString())) {
@@ -93,7 +95,8 @@ public function enterNode(Node $node): void
          *
          * @see FileVisitorTest::test_should_returns_all_dependencies
          */
-        if ($node instanceof Node\Expr\StaticCall
+        if (
+            $node instanceof Node\Expr\StaticCall
             && method_exists($node->class, 'toString')
         ) {
             if ($this->isSelfOrStaticOrParent($node->class->toString())) {
@@ -104,7 +107,8 @@ public function enterNode(Node $node): void
                 ->addDependency(new ClassDependency($node->class->toString(), $node->getLine()));
         }
 
-        if ($node instanceof Node\Expr\Instanceof_
+        if (
+            $node instanceof Node\Expr\Instanceof_
             && method_exists($node->class, 'toString')
         ) {
             if ($this->isSelfOrStaticOrParent($node->class->toString())) {
@@ -114,11 +118,13 @@ public function enterNode(Node $node): void
                 ->addDependency(new ClassDependency($node->class->toString(), $node->getLine()));
         }
 
-        if ($node instanceof Node\Expr\New_
+        if (
+            $node instanceof Node\Expr\New_
             && !($node->class instanceof Node\Expr\Variable)
         ) {
-            if ((method_exists($node->class, 'isAnonymous') && $node->class->isAnonymous())
-                || !method_exists($node->class, 'toString')) {
+            if ((method_exists($node->class, 'isAnonymous') && true === $node->class->isAnonymous())
+                || !method_exists($node->class, 'toString')
+            ) {
                 return;
             }
 
@@ -215,7 +221,7 @@ public function enterNode(Node $node): void
             $returnType = $node->returnType;
             if ($returnType instanceof Node\Name\FullyQualified) {
                 $this->classDescriptionBuilder
-                  ->addDependency(new ClassDependency($returnType->toString(), $returnType->getLine()));
+                    ->addDependency(new ClassDependency($returnType->toString(), $returnType->getLine()));
             }
         }
     }
@@ -271,7 +277,7 @@ private function addParamDependency(Node\Param $node): void
             $type = $nullableType->type;
         }
 
-        if (method_exists($type, 'isSpecialClassName') && $type->isSpecialClassName()) {
+        if (method_exists($type, 'isSpecialClassName') && true === $type->isSpecialClassName()) {
             return;
         }
 
diff --git a/src/CLI/Command/Check.php b/src/CLI/Command/Check.php
index 63534770..468b1808 100644
--- a/src/CLI/Command/Check.php
+++ b/src/CLI/Command/Check.php
@@ -97,11 +97,11 @@ protected function execute(InputInterface $input, OutputInterface $output): int
         $startTime = microtime(true);
 
         try {
-            $verbose = $input->getOption('verbose');
-            $stopOnFailure = $input->getOption(self::STOP_ON_FAILURE_PARAM);
-            $useBaseline = $input->getOption(self::USE_BASELINE_PARAM);
-            $skipBaseline = $input->getOption(self::SKIP_BASELINE_PARAM);
-            $ignoreBaselineLinenumbers = $input->getOption(self::IGNORE_BASELINE_LINENUMBERS_PARAM);
+            $verbose = (bool) $input->getOption('verbose');
+            $stopOnFailure = (bool) $input->getOption(self::STOP_ON_FAILURE_PARAM);
+            $useBaseline = (string) $input->getOption(self::USE_BASELINE_PARAM);
+            $skipBaseline = (bool) $input->getOption(self::SKIP_BASELINE_PARAM);
+            $ignoreBaselineLinenumbers = (bool) $input->getOption(self::IGNORE_BASELINE_LINENUMBERS_PARAM);
 
             if (true !== $skipBaseline && !$useBaseline && file_exists(self::DEFAULT_BASELINE_FILENAME)) {
                 $useBaseline = self::DEFAULT_BASELINE_FILENAME;
diff --git a/src/ClassSet.php b/src/ClassSet.php
index 519a8953..d654c1c5 100644
--- a/src/ClassSet.php
+++ b/src/ClassSet.php
@@ -1,10 +1,14 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Arkitect;
 
 use Symfony\Component\Finder\Finder;
 
+/**
+ * @template-implements \IteratorAggregate<string, \Symfony\Component\Finder\SplFileInfo>
+ */
 class ClassSet implements \IteratorAggregate
 {
     /** @var string */
diff --git a/src/PHPUnit/ArchRuleCheckerConstraintAdapter.php b/src/PHPUnit/ArchRuleCheckerConstraintAdapter.php
index fd468933..f143c125 100644
--- a/src/PHPUnit/ArchRuleCheckerConstraintAdapter.php
+++ b/src/PHPUnit/ArchRuleCheckerConstraintAdapter.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Arkitect\PHPUnit;
@@ -10,11 +11,17 @@
 use Arkitect\CLI\Progress\VoidProgress;
 use Arkitect\CLI\Runner;
 use Arkitect\CLI\TargetPhpVersion;
-use Arkitect\Rules\ArchRule;
 use Arkitect\Rules\ParsingErrors;
 use Arkitect\Rules\Violations;
 use PHPUnit\Framework\Constraint\Constraint;
 
+/**
+ * @psalm-suppress UndefinedClass
+ *
+ * Since we declared phpunit as a dev dependency we cannot be sure the class PHPUnit\Framework\Constraint\Constraint
+ * will be available at runtime. Given arkitect will be used in a development environment, we can ignore this but it
+ * would be nice to have a way to check if the class is available at runtime.
+ */
 class ArchRuleCheckerConstraintAdapter extends Constraint
 {
     /** @var ClassSet */
@@ -47,8 +54,10 @@ public function toString(): string
         return 'satisfies all architectural constraints';
     }
 
-    protected function matches(/** @var $rule ArchRule */ $other): bool
-    {
+    protected function matches(
+        /** @var $rule ArchRule */
+        $other
+    ): bool {
         $this->runner->check(
             ClassSetRules::create($this->classSet, $other),
             new VoidProgress(),
diff --git a/src/Rules/ParsingErrors.php b/src/Rules/ParsingErrors.php
index 007ce001..bc475037 100644
--- a/src/Rules/ParsingErrors.php
+++ b/src/Rules/ParsingErrors.php
@@ -1,10 +1,14 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Arkitect\Rules;
 
 use Arkitect\Exceptions\IndexNotFoundException;
 
+/**
+ * @template-implements \IteratorAggregate<ParsingError>
+ */
 class ParsingErrors implements \IteratorAggregate, \Countable
 {
     /**
diff --git a/src/Rules/Violations.php b/src/Rules/Violations.php
index 48c24879..add25ad4 100644
--- a/src/Rules/Violations.php
+++ b/src/Rules/Violations.php
@@ -7,12 +7,16 @@
 use Arkitect\Exceptions\FailOnFirstViolationException;
 use Arkitect\Exceptions\IndexNotFoundException;
 
+/**
+ * @template-implements \IteratorAggregate<Violation>
+ */
 class Violations implements \IteratorAggregate, \Countable, \JsonSerializable
 {
     /**
      * @var Violation[]
      */
     private $violations;
+
     /**
      * @var bool
      */