diff --git a/lib/Migrator.php b/lib/Migrator.php
index 6602eea..7e450ee 100644
--- a/lib/Migrator.php
+++ b/lib/Migrator.php
@@ -57,7 +57,7 @@ public function initialize()
      * If $to is 0 then all migrations will be reverted.
      * If $to is null then all migrations will be executed.
      *
-     * @param string|null $to Version to run until
+     * @param string|int|boolean|null $to Version to run until
      *
      * @return VersionInterface[] Executed migrations
      */
diff --git a/lib/MigratorUtil.php b/lib/MigratorUtil.php
index 56d9e26..69e34be 100644
--- a/lib/MigratorUtil.php
+++ b/lib/MigratorUtil.php
@@ -24,7 +24,7 @@ class MigratorUtil
      */
     public static function getClassNameFromFile($file)
     {
-        $fp = fopen($file, 'r');
+        $fp = fopen($file, 'rb');
 
         $class = $namespace = $buffer = '';
         $i = 0;
@@ -39,15 +39,16 @@ public static function getClassNameFromFile($file)
                 $buffer .= fgets($fp);
             }
             $tokens = @token_get_all($buffer);
+            $tokensCount = count($tokens);
 
             if (false === strpos($buffer, '{')) {
                 continue;
             }
 
-            for (; $i < count($tokens); ++$i) {
+            for (; $i < $tokensCount; ++$i) {
                 if (T_NAMESPACE === $tokens[$i][0]) {
-                    for ($j = $i + 1; $j < count($tokens); ++$j) {
-                        if (\defined('T_NAME_QUALIFIED') && T_NAME_QUALIFIED === $tokens[$j][0] || T_STRING === $tokens[$j][0]) {
+                    for ($j = $i + 1; $j < $tokensCount; ++$j) {
+                        if (T_STRING === $tokens[$j][0] || (\defined('T_NAME_QUALIFIED') && T_NAME_QUALIFIED === $tokens[$j][0])) {
                             $namespace .= '\\'.$tokens[$j][1];
                         } elseif ('{' === $tokens[$j] || ';' === $tokens[$j]) {
                             break;
@@ -56,7 +57,7 @@ public static function getClassNameFromFile($file)
                 }
 
                 if (T_CLASS === $tokens[$i][0]) {
-                    for ($j = $i + 1; $j < count($tokens); ++$j) {
+                    for ($j = $i + 1; $j < $tokensCount; ++$j) {
                         if ('{' === $tokens[$j]) {
                             $class = $tokens[$i + 2][1];
                         }
@@ -66,7 +67,7 @@ public static function getClassNameFromFile($file)
         }
 
         if (!$class) {
-            return;
+            throw new \RuntimeException('Could not determine class for migration');
         }
 
         return $namespace.'\\'.$class;
diff --git a/lib/VersionCollection.php b/lib/VersionCollection.php
index cbdbcb1..ad55c74 100644
--- a/lib/VersionCollection.php
+++ b/lib/VersionCollection.php
@@ -86,7 +86,7 @@ public function getLatestVersion()
     /**
      * Return the version after the given version.
      *
-     * @param string $from
+     * @param string|null $from
      */
     public function getNextVersion($from)
     {
@@ -105,8 +105,6 @@ public function getNextVersion($from)
                 return $timestamp;
             }
         }
-
-        return;
     }
 
     /**
@@ -126,9 +124,4 @@ public function getPreviousVersion($from)
 
         return 0;
     }
-
-    private function normalizeTs($ts)
-    {
-        return $ts ? $ts : null;
-    }
 }
diff --git a/lib/VersionStorage.php b/lib/VersionStorage.php
index d743bee..4cb98af 100644
--- a/lib/VersionStorage.php
+++ b/lib/VersionStorage.php
@@ -11,6 +11,7 @@
 
 namespace PHPCR\Migrations;
 
+use PHPCR\NodeInterface;
 use PHPCR\SessionInterface;
 
 class VersionStorage
@@ -18,6 +19,10 @@ class VersionStorage
     private $session;
     private $storageNodeName;
     private $initialized = false;
+    /**
+     * @var NodeInterface
+     */
+    private $storageNode;
 
     public function __construct(SessionInterface $session, $storageNodeName = 'phpcrmig:versions')
     {
@@ -31,8 +36,8 @@ public function init()
             return;
         }
 
-        $this->workspace = $this->session->getWorkspace();
-        $nodeTypeManager = $this->workspace->getNodeTypeManager();
+        $workspace = $this->session->getWorkspace();
+        $nodeTypeManager = $workspace->getNodeTypeManager();
 
         if (!$nodeTypeManager->hasNodeType('phpcrmig:version')) {
             $nodeTypeManager->registerNodeTypesCnd(<<<EOT
@@ -47,13 +52,10 @@ public function init()
 
         $rootNode = $this->session->getRootNode();
 
-        if ($rootNode->hasNode($this->storageNodeName)) {
-            $storageNode = $rootNode->getNode($this->storageNodeName);
-        } else {
-            $storageNode = $rootNode->addNode($this->storageNodeName, 'phpcrmig:versions');
-        }
-
-        $this->storageNode = $storageNode;
+        $this->storageNode = ($rootNode->hasNode($this->storageNodeName))
+            ? $rootNode->getNode($this->storageNodeName)
+            : $rootNode->addNode($this->storageNodeName, 'phpcrmig:versions')
+        ;
     }
 
     public function getPersistedVersions()
@@ -85,7 +87,7 @@ public function getCurrentVersion()
         $versions = (array) $this->storageNode->getNodeNames();
 
         if (!$versions) {
-            return;
+            return null;
         }
 
         asort($versions);
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..1be1e0e
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,5 @@
+parameters:
+    level: 5
+    reportUnmatchedIgnoredErrors: false
+    paths:
+        - lib/