diff --git a/composer.json b/composer.json
index 09dca6d..7b2ebde 100644
--- a/composer.json
+++ b/composer.json
@@ -22,18 +22,18 @@
     },
     "require-dev": {
         "edgedesign/phpqa": "^v1.25",
-        "phpunit/phpunit": "^8.0",
         "friendsofphp/php-cs-fixer": "^3.0",
-        "vimeo/psalm": "^4.3",
         "php-parallel-lint/php-parallel-lint": "^1.0",
-        "phpstan/phpstan": "^0.12",
-        "phpstan/phpstan-phpunit": "^0.12"
+        "phpstan/phpstan": "^1.2",
+        "phpstan/phpstan-phpunit": "^1.0",
+        "phpunit/phpunit": "^8.0",
+        "vimeo/psalm": "^4.3"
     },
     "minimum-stability": "stable",
     "scripts": {
         "cs-fix": "@php ./vendor/bin/php-cs-fixer fix",
         "phpqa": "@php ./vendor/bin/phpqa --report --tools phpcs:0,phpmetrics,phploc,pdepend,security-checker:0,parallel-lint:0 --ignoredDirs vendor,tests",
-        "phpstan": "@php ./vendor/bin/phpstan analyse src --level 5 -c extension.neon",
+        "phpstan": "@php ./vendor/bin/phpstan analyse src --level 6 -c extension.neon",
         "psalm": "@php ./vendor/bin/psalm --threads=8 --diff",
         "test": "@php ./vendor/bin/phpunit"
     },
diff --git a/extension.neon b/extension.neon
index 94700c5..3ff206e 100644
--- a/extension.neon
+++ b/extension.neon
@@ -4,3 +4,4 @@ includes:
 
 parameters:
 	treatPhpDocTypesAsCertain: false
+	checkMissingIterableValueType: false
diff --git a/src/Entity/Comment.php b/src/Entity/Comment.php
index d8fc781..f14acda 100644
--- a/src/Entity/Comment.php
+++ b/src/Entity/Comment.php
@@ -34,11 +34,7 @@ final public function __construct($data)
         $this->htmlUrl = $data['html_url'] ?? '';
         $this->id = $data['id'] ?? '';
 
-        if (is_array($data['user'])) {
-            $user = $data['user'];
-        } else {
-            $user = [];
-        }
+        $user = is_array($data['user']) ? $data['user'] : [];
 
         $this->user = User::createFromData($user);
         $this->position = isset($data['position']) ? $data['position'] : '';
diff --git a/src/Entity/CommitUser.php b/src/Entity/CommitUser.php
index e283681..6bb2f34 100644
--- a/src/Entity/CommitUser.php
+++ b/src/Entity/CommitUser.php
@@ -4,7 +4,10 @@
 
 class CommitUser
 {
-    private $date;
+    /**
+     * @var \DateTime|\DateTimeImmutable
+     */
+    private \DateTimeInterface $date;
     private $name;
     private $email;
 
diff --git a/src/Entity/Deployment.php b/src/Entity/Deployment.php
index decadf5..f202b94 100644
--- a/src/Entity/Deployment.php
+++ b/src/Entity/Deployment.php
@@ -13,10 +13,7 @@ class Deployment
     private $environment;
     private $description;
 
-    /**
-     * @var User
-     */
-    private $creator;
+    private \LoveOSS\Github\Entity\User $creator;
     private $createdAt;
     private $updatedAt;
     private $statusesUrl;
diff --git a/src/Entity/Integration.php b/src/Entity/Integration.php
index e48f988..c9cbf41 100644
--- a/src/Entity/Integration.php
+++ b/src/Entity/Integration.php
@@ -9,10 +9,7 @@ class Integration
      */
     private $installationId;
 
-    /**
-     * @var User
-     */
-    private $account;
+    private ?\LoveOSS\Github\Entity\User $account = null;
 
     /**
      * @var string
diff --git a/src/Entity/Issue.php b/src/Entity/Issue.php
index fdde2d6..b118512 100644
--- a/src/Entity/Issue.php
+++ b/src/Entity/Issue.php
@@ -13,19 +13,13 @@ class Issue
     private $number;
     private $title;
 
-    /**
-     * @var User
-     */
-    private $user;
-    private $labels;
+    private \LoveOSS\Github\Entity\User $user;
+    private array $labels;
     private $state;
     private $isLocked;
 
-    /**
-     * @var User|null
-     */
-    private $assignee;
-    private $milestone;
+    private ?\LoveOSS\Github\Entity\User $assignee = null;
+    private ?bool $milestone = null;
     private $commentsCount;
     private $createdAt;
     private $updatedAt;
diff --git a/src/Entity/PullRequest.php b/src/Entity/PullRequest.php
index a302dfa..2e20607 100644
--- a/src/Entity/PullRequest.php
+++ b/src/Entity/PullRequest.php
@@ -67,7 +67,7 @@ final public function __construct($data)
         $this->htmlUrl = $data['html_url'];
         $diffUrl = isset($data['diff_url']) ? $data['diff_url'] : null;
         $diffUrlFromPR = isset($data['pull_request']['diff_url']) ? $data['pull_request']['diff_url'] : null;
-        $this->diffUrl = !is_null($diffUrl) ? $diffUrl : $diffUrlFromPR;
+        $this->diffUrl = is_null($diffUrl) ? $diffUrlFromPR : $diffUrl;
         $this->issueUrl = isset($data['issue_url']) ? $data['issue_url'] : null;
         $this->number = $data['number'];
         $this->state = $data['state'];
diff --git a/src/Entity/Release.php b/src/Entity/Release.php
index 0fa60cb..348be88 100644
--- a/src/Entity/Release.php
+++ b/src/Entity/Release.php
@@ -13,7 +13,7 @@ class Release
     private $targetCommitish;
     private $name;
     private $isDraft;
-    private $author;
+    private \LoveOSS\Github\Entity\User $author;
     private $isPreRelease;
     private $createdAt;
     private $publishedAt;
@@ -21,8 +21,8 @@ class Release
     private $tarballUrl;
     private $zipballUrl;
     private $body;
-    private $repository;
-    private $sender;
+    private \LoveOSS\Github\Entity\Repository $repository;
+    private \LoveOSS\Github\Entity\User $sender;
 
     public static function createFromData(array $data, Repository $repository, User $sender)
     {
diff --git a/src/Entity/Repository.php b/src/Entity/Repository.php
index 43668a1..fc9a993 100644
--- a/src/Entity/Repository.php
+++ b/src/Entity/Repository.php
@@ -8,10 +8,7 @@ class Repository
     private $name;
     private $fullName;
 
-    /**
-     * @var User
-     */
-    private $owner;
+    private \LoveOSS\Github\Entity\User $owner;
     private $isPrivate;
     private $htmlUrl;
     private $description;
@@ -73,7 +70,7 @@ class Repository
     private $openIssues;
     private $watchers;
     private $defaultBranch;
-    private $isPublic;
+    private ?bool $isPublic = null;
 
     public static function createFromData(array $data)
     {
diff --git a/src/EventType/AbstractEventType.php b/src/EventType/AbstractEventType.php
index cca5a61..c28ad5e 100644
--- a/src/EventType/AbstractEventType.php
+++ b/src/EventType/AbstractEventType.php
@@ -28,7 +28,7 @@ public static function name(): string
     public static function isValid(array $data): bool
     {
         foreach (static::fields() as $field) {
-            if ((isset($data[$field]) || array_key_exists($field, $data)) === false) {
+            if (!isset($data[$field]) && !array_key_exists($field, $data)) {
                 return false;
             }
         }
diff --git a/src/EventType/DeploymentStatusEvent.php b/src/EventType/DeploymentStatusEvent.php
index be2b4e8..db03ce8 100644
--- a/src/EventType/DeploymentStatusEvent.php
+++ b/src/EventType/DeploymentStatusEvent.php
@@ -12,10 +12,7 @@ class DeploymentStatusEvent extends RepositoryAwareEventType
      */
     public $deployment;
 
-    /**
-     * @var User
-     */
-    public $sender;
+    public ?\LoveOSS\Github\Entity\User $sender = null;
 
     public static function name(): string
     {
diff --git a/src/EventType/ForkEvent.php b/src/EventType/ForkEvent.php
index 23dbda9..1884737 100644
--- a/src/EventType/ForkEvent.php
+++ b/src/EventType/ForkEvent.php
@@ -17,10 +17,7 @@ class ForkEvent extends RepositoryAwareEventType
      */
     public $owner;
 
-    /**
-     * @var User
-     */
-    public $forker;
+    public ?\LoveOSS\Github\Entity\User $forker = null;
 
     public static function name(): string
     {
diff --git a/src/EventType/PullRequestReviewCommentEvent.php b/src/EventType/PullRequestReviewCommentEvent.php
index 1fa486d..4c0ae12 100644
--- a/src/EventType/PullRequestReviewCommentEvent.php
+++ b/src/EventType/PullRequestReviewCommentEvent.php
@@ -33,13 +33,7 @@ public static function fields(): array
 
     public static function isValid($data): bool
     {
-        if (parent::isValid($data)) {
-            if ($data['action'] === 'created') {
-                return true;
-            }
-        }
-
-        return false;
+        return parent::isValid($data) && $data['action'] === 'created';
     }
 
     public function createFromData($data): self
diff --git a/src/EventType/PushEvent.php b/src/EventType/PushEvent.php
index 9bb2281..1c76b5f 100644
--- a/src/EventType/PushEvent.php
+++ b/src/EventType/PushEvent.php
@@ -26,7 +26,7 @@ public static function fields(): array
         return ['ref', 'head', 'before', 'commits'];
     }
 
-    public function createFromData($data): self
+    public function createFromData(array $data): self
     {
         parent::createFromData($data);
 
diff --git a/src/EventType/ReleaseEvent.php b/src/EventType/ReleaseEvent.php
index a338285..ce672bc 100644
--- a/src/EventType/ReleaseEvent.php
+++ b/src/EventType/ReleaseEvent.php
@@ -7,11 +7,11 @@
 
 class ReleaseEvent extends RepositoryAwareEventType implements ActionableEventInterface
 {
-    public $action;
+    public string $action;
 
     public Release $release;
 
-    public function getAction()
+    public function getAction(): string
     {
         return $this->action;
     }
@@ -26,7 +26,7 @@ public static function fields(): array
         return ['action', 'release', 'sender', 'repository'];
     }
 
-    public function createFromData($data): self
+    public function createFromData(array $data): self
     {
         parent::createFromData($data);
 
diff --git a/src/EventType/RepositoryAwareEventType.php b/src/EventType/RepositoryAwareEventType.php
index 7e1a522..6744f85 100644
--- a/src/EventType/RepositoryAwareEventType.php
+++ b/src/EventType/RepositoryAwareEventType.php
@@ -14,7 +14,7 @@ public function getRepository(): Repository
         return $this->repository;
     }
 
-    public function createFromData($data): self
+    public function createFromData(array $data): self
     {
         parent::createFromData($data);
 
diff --git a/src/EventType/StatusEvent.php b/src/EventType/StatusEvent.php
index 8fc2ae5..c34ae97 100644
--- a/src/EventType/StatusEvent.php
+++ b/src/EventType/StatusEvent.php
@@ -6,7 +6,7 @@
 
 class StatusEvent extends RepositoryAwareEventType
 {
-    public $branches;
+    public array $branches;
 
     public User $committer;
     public string $description;
@@ -24,7 +24,7 @@ public static function fields(): array
         return ['sha', 'state', 'description', 'target_url', 'branches'];
     }
 
-    public function createFromData($data): self
+    public function createFromData(array $data): self
     {
         parent::createFromData($data);
 
diff --git a/src/EventType/WatchEvent.php b/src/EventType/WatchEvent.php
index 1aa92bb..a7ab8b9 100644
--- a/src/EventType/WatchEvent.php
+++ b/src/EventType/WatchEvent.php
@@ -6,11 +6,11 @@
 
 class WatchEvent extends RepositoryAwareEventType implements ActionableEventInterface
 {
-    public $action;
+    public string $action;
 
     public User $user;
 
-    public function getAction()
+    public function getAction(): string
     {
         return $this->action;
     }
@@ -25,16 +25,12 @@ public static function fields(): array
         return ['action'];
     }
 
-    public static function isValid($data): bool
+    public static function isValid(array $data): bool
     {
-        if (array_key_exists('action', $data) && $data['action'] === 'started') {
-            return true;
-        }
-
-        return false;
+        return array_key_exists('action', $data) && $data['action'] === 'started';
     }
 
-    public function createFromData($data): self
+    public function createFromData(array $data): self
     {
         parent::createFromData($data);
 
diff --git a/src/Exception/RepositoryNotFoundException.php b/src/Exception/RepositoryNotFoundException.php
index 17a0ed4..a38daaf 100644
--- a/src/Exception/RepositoryNotFoundException.php
+++ b/src/Exception/RepositoryNotFoundException.php
@@ -6,7 +6,7 @@
 
 class RepositoryNotFoundException extends Exception
 {
-    public function __construct($errorMessage)
+    public function __construct(string $errorMessage)
     {
         $exceptionMessage = sprintf("A repository can't be extracted from data: %s", $errorMessage);
 
diff --git a/src/Parser/WebhookResolver.php b/src/Parser/WebhookResolver.php
index b21f914..bfda41b 100644
--- a/src/Parser/WebhookResolver.php
+++ b/src/Parser/WebhookResolver.php
@@ -2,11 +2,12 @@
 
 namespace LoveOSS\Github\Parser;
 
+use LoveOSS\Github\EventType\GithubEventInterface;
 use LoveOSS\Github\Exception\EventNotFoundException;
 
 class WebhookResolver
 {
-    public function resolve(array $data)
+    public function resolve(array $data): GithubEventInterface
     {
         foreach ($this->eventsType() as $eventType) {
             if ($eventType['class']::isValid($data)) {
@@ -17,7 +18,7 @@ public function resolve(array $data)
         throw new EventNotFoundException();
     }
 
-    public function eventsType()
+    public function eventsType(): array
     {
         $classes = [
             'LoveOSS\Github\EventType\IssuesEvent',
@@ -45,7 +46,7 @@ public function eventsType()
         }
 
         usort($eventTypes, function ($a, $b) {
-            if ($a['priority'] == $b['priority']) {
+            if ($a['priority'] === $b['priority']) {
                 return 0;
             }