diff --git a/AbortStageException.php b/AbortStageException.php
index f793e2b..a2374d0 100644
--- a/AbortStageException.php
+++ b/AbortStageException.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * Copyright Zikula Foundation 2014.
  *
diff --git a/FormHandlerInterface.php b/FormHandlerInterface.php
index 11b4435..259785d 100644
--- a/FormHandlerInterface.php
+++ b/FormHandlerInterface.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * Copyright Zikula Foundation 2014.
  *
@@ -21,22 +24,16 @@ interface FormHandlerInterface
 {
     /**
      * Returns the FQCN of a Symfony Form Type
-     *
-     * @return string
      */
-    public function getFormType();
+    public function getFormType(): string;
 
     /**
      * Handle results of previously validated form
-     *
-     * @param FormInterface $form
-     * @return boolean
      */
-    public function handleFormResult(FormInterface $form);
+    public function handleFormResult(FormInterface $form): bool;
 
     /**
      * Returns an array of options applied to the Form.
-     * @return array
      */
-    public function getFormOptions();
+    public function getFormOptions(): array;
 }
diff --git a/InjectContainerInterface.php b/InjectContainerInterface.php
index ca4ff14..e2c0367 100644
--- a/InjectContainerInterface.php
+++ b/InjectContainerInterface.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * Copyright Zikula Foundation 2014.
  *
@@ -21,8 +24,6 @@ interface InjectContainerInterface
 {
     /**
      * Require the Symfony Container on instantiation
-     *
-     * @param ContainerInterface $container
      */
     public function __construct(ContainerInterface $container);
 }
diff --git a/StageInterface.php b/StageInterface.php
index 615aa6e..e80b79b 100644
--- a/StageInterface.php
+++ b/StageInterface.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * Copyright Zikula Foundation 2014.
  *
@@ -19,29 +22,23 @@ interface StageInterface
 {
     /**
      * The stage name
-     *
-     * @return string
      */
-    public function getName();
+    public function getName(): string;
 
     /**
      * The stage's full template name, e.g. 'AcmeDemoBundle:Stage:prep.html.twig'
-     * @return string
      */
-    public function getTemplateName();
+    public function getTemplateName(): string;
 
     /**
      * Logic to determine if the stage is required or can be skipped
      *
-     * @return boolean
      * @throws AbortStageException
      */
-    public function isNecessary();
+    public function isNecessary(): bool;
 
     /**
      * An array of template parameters required in the stage template
-     *
-     * @return array
      */
-    public function getTemplateParams();
+    public function getTemplateParams(): array;
 }
diff --git a/Wizard.php b/Wizard.php
index 01cf87a..4dbf028 100644
--- a/Wizard.php
+++ b/Wizard.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * Copyright Zikula Foundation 2014.
  *
@@ -16,33 +19,57 @@
 namespace Zikula\Component\Wizard;
 
 use Gedmo\Exception\RuntimeException;
+use InvalidArgumentException;
 use Symfony\Component\Config\Exception\FileLoaderLoadException;
 use Symfony\Component\Config\FileLocator;
-use Symfony\Component\Debug\Exception\ClassNotFoundException;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
  * Class Wizard
- * @package Zikula\Component\Wizard
  */
 class Wizard
 {
+    /**
+     * @var ContainerInterface
+     */
     private $container;
+
+    /**
+     * @var array
+     */
     private $stagesByName = [];
+
+    /**
+     * @var array
+     */
     private $stageOrder = [];
+
+    /**
+     * @var string
+     */
     private $defaultStage;
+
+    /**
+     * @var string
+     */
     private $currentStageName;
-    private $YamlFileLoader;
+
+    /**
+     * @var YamlFileLoader
+     */
+    private $yamlFileLoader;
+
+    /**
+     * @var string
+     */
     private $warning = '';
 
     /**
      * Constructor.
      *
-     * @param ContainerInterface $container
-     * @param string $path including filename, e.g. my/full/path/to/my/stages.yml
      * @throws FileLoaderLoadException
      */
-    function __construct(ContainerInterface $container, $path)
+    public function __construct(ContainerInterface $container, string $path)
     {
         $this->container = $container;
         if (!empty($path)) {
@@ -55,10 +82,9 @@ function __construct(ContainerInterface $container, $path)
     /**
      * Load the stage definitions from $path
      *
-     * @param string $path including filename, e.g. my/full/path/to/my/stages.yml
      * @throws FileLoaderLoadException
      */
-    public function loadStagesFromYaml($path)
+    public function loadStagesFromYaml(string $path): void
     {
         if (!file_exists($path)) {
             throw new FileLoaderLoadException('Stage definition file cannot be found.');
@@ -67,12 +93,14 @@ public function loadStagesFromYaml($path)
         if ($pathInfo['extension'] !== 'yml') {
             throw new FileLoaderLoadException('Stage definition file must include .yml extension.');
         }
-        $this->stages = []; // empty the stages
-        if (!isset($this->YamlFileLoader)) {
-            $this->YamlFileLoader = new YamlFileLoader(new FileLocator($pathInfo['dirname']));
+
+        // empty the stages
+        $this->stagesByName = [];
+        if (!isset($this->yamlFileLoader)) {
+            $this->yamlFileLoader = new YamlFileLoader(new FileLocator($pathInfo['dirname']));
         }
-        $this->YamlFileLoader->load($pathInfo['basename']);
-        $stages = $this->YamlFileLoader->getContent();
+        $this->yamlFileLoader->load($pathInfo['basename']);
+        $stages = $this->yamlFileLoader->getContent();
         $stages = $stages['stages'];
         foreach ($stages as $key => $stageArray) {
             $this->stagesByName[$key] = $stageArray['class'];
@@ -85,16 +113,14 @@ public function loadStagesFromYaml($path)
 
     /**
      * Get the stage that is the first necessary stage
-     *
-     * @param $name
-     * @return StageInterface
      */
-    public function getCurrentStage($name)
+    public function getCurrentStage(string $name): StageInterface
     {
         // compute the stageClass from Request parameter
         $stageClass = $this->getStageClassName($name);
 
         // loop each stage until finds the first that is necessary
+
         do {
             $useCurrentStage = false;
             /** @var StageInterface $currentStage */
@@ -113,38 +139,31 @@ public function getCurrentStage($name)
             } else {
                 $currentStage = $this->getNextStage();
             }
-        } while ($useCurrentStage == false);
+        } while (false === $useCurrentStage);
 
         return $currentStage;
     }
 
     /**
      * Get an instance of the previous stage
-     *
-     * @return StageInterface
      */
-    public function getPreviousStage()
+    public function getPreviousStage(): StageInterface
     {
         return $this->getSequentialStage('prev');
     }
 
     /**
      * Get an instance of the next stage
-     *
-     * @return StageInterface
      */
-    public function getNextStage()
+    public function getNextStage(): StageInterface
     {
         return $this->getSequentialStage('next');
     }
 
     /**
-     * get either previous or next stage
-     *
-     * @param $direction (prev|next)
-     * @return StageInterface|null
+     * Get either previous or next stage
      */
-    private function getSequentialStage($direction)
+    private function getSequentialStage(string $direction): ?StageInterface
     {
         $dir = in_array($direction, ['prev', 'next']) ? $direction : 'next';
         ksort($this->stageOrder);
@@ -154,7 +173,6 @@ private function getSequentialStage($direction)
         }
         $key = $dir($this->stageOrder);
         if (null !== $key && false !== $key) {
-
             return $this->getStageInstance($this->stagesByName[$key]);
         }
 
@@ -163,61 +181,48 @@ private function getSequentialStage($direction)
 
     /**
      * Factory class to instantiate a StageClass
-     *
-     * @param $stageClass
-     * @return StageInterface
      */
-    private function getStageInstance($stageClass)
+    private function getStageInstance(string $stageClass): StageInterface
     {
         if (!class_exists($stageClass)) {
             throw new RuntimeException('Error: Could not find requested stage class.');
         }
-        if (in_array("Zikula\\Component\\Wizard\\InjectContainerInterface", class_implements($stageClass))) {
-
+        if (in_array("Zikula\\Component\\Wizard\\InjectContainerInterface", class_implements($stageClass), true)) {
             return new $stageClass($this->container);
-        } else {
-
-            return new $stageClass();
         }
+
+        return new $stageClass();
     }
 
     /**
      * Has the wizard been halted?
-     *
-     * @return bool
      */
-    public function isHalted()
+    public function isHalted(): bool
     {
-        return (!empty($this->warning));
+        return !empty($this->warning);
     }
 
     /**
-     * get any warning currently set
-     *
-     * @return string
+     * Get any warning currently set
      */
-    public function getWarning()
+    public function getWarning(): string
     {
-        return "WARNING: The Wizard was halted for the following reason. This must be corrected before you can continue. " . $this->warning;
+        return 'WARNING: The Wizard was halted for the following reason. This must be corrected before you can continue. ' . $this->warning;
     }
 
     /**
      * Match the stage and return the stage classname or default.
      *
-     * @param $name
-     * @return string
-     * @throws \InvalidArgumentException
+     * @throws InvalidArgumentException
      */
-    private function getStageClassName($name)
+    private function getStageClassName(string $name): string
     {
         if (!empty($this->stagesByName[$name])) {
-
             return $this->stagesByName[$name];
         }
         if (!empty($this->defaultStage) && !empty($this->stagesByName[$this->defaultStage])) {
-
             return $this->stagesByName[$this->defaultStage];
         }
-        throw new \InvalidArgumentException('The request stage could not be found and there is no default stage defined.');
+        throw new InvalidArgumentException('The request stage could not be found and there is no default stage defined.');
     }
 }
diff --git a/WizardCompleteInterface.php b/WizardCompleteInterface.php
index 92a1e65..5f2b92e 100644
--- a/WizardCompleteInterface.php
+++ b/WizardCompleteInterface.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * Copyright Zikula Foundation 2014.
  *
@@ -16,14 +19,12 @@
 namespace Zikula\Component\Wizard;
 
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
 
 interface WizardCompleteInterface
 {
     /**
-     * Get the Response (probably RedirectResponse) for this completed Wizard
-     *
-     * @param Request $request
-     * @return \Symfony\Component\HttpFoundation\Response;
+     * Get the Response (probably RedirectResponse) for this completed Wizard.
      */
-    public function getResponse(Request $request);
+    public function getResponse(Request $request): Response;
 }
diff --git a/YamlFileLoader.php b/YamlFileLoader.php
index af0d7a3..deab000 100644
--- a/YamlFileLoader.php
+++ b/YamlFileLoader.php
@@ -1,16 +1,14 @@
 <?php
-/**
- * Copyright Zikula Foundation 2014.
- *
- * This work is contributed to the Zikula Foundation under one or more
- * Contributor Agreements and licensed to You under the following license:
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the Zikula package.
  *
- * @license MIT.
- * @package Zikula
- * @author Craig Heydenburg
+ * Copyright Zikula Foundation - https://ziku.la/
  *
- * Please see the LICENSE file distributed with this source code for further
- * information regarding copyright and licensing.
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 namespace Zikula\Component\Wizard;
@@ -45,10 +43,7 @@ public function supports($resource, $type = null)
         return is_string($resource) && 'yml' === pathinfo($resource, PATHINFO_EXTENSION);
     }
 
-    /**
-     * @return array|null
-     */
-    public function getContent()
+    public function getContent(): ?array
     {
         return $this->content;
     }
@@ -56,13 +51,9 @@ public function getContent()
     /**
      * Loads a YAML file.
      *
-     * @param string $file
-     *
-     * @return array The file content
-     *
      * @throws InvalidArgumentException when the given file is not a local file or when it does not exist
      */
-    private function loadFile($file)
+    private function loadFile(string $file): array
     {
         if (!stream_is_local($file)) {
             throw new InvalidArgumentException(sprintf('This is not a local file "%s".', $file));
@@ -82,14 +73,12 @@ private function loadFile($file)
     /**
      * Validates a YAML file.
      *
-     * @param mixed  $content
-     * @param string $file
-     *
+     * @param mixed $content
      * @return array
      *
      * @throws InvalidArgumentException When service file is not valid
      */
-    private function validate($content, $file)
+    private function validate($content, string $file): array
     {
         if (null === $content) {
             return $content;
@@ -99,10 +88,8 @@ private function validate($content, $file)
             throw new InvalidArgumentException(__f('The yaml file "%s" is not valid. It should contain an array. Check your YAML syntax.', $file));
         }
 
-        if (isset($content['stages'])) {
-            if (!is_array($content['stages'])) {
-                throw new InvalidArgumentException(__f('The "stages" key should contain an array in %s. Check your YAML syntax.', $file));
-            }
+        if (isset($content['stages']) && !is_array($content['stages'])) {
+            throw new InvalidArgumentException(__f('The "stages" key should contain an array in %s. Check your YAML syntax.', $file));
         }
 
         return $content;