diff --git a/CHANGELOG.md b/CHANGELOG.md
index 434f037..2d8b00e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [4.3.1]
+- Improved code quality & type hinting
+- Fixed issue where an empty Yaml file would produce a null. Now returns an empty array
+- `UserFrosting\Support\DotenvEditor\DotenvEditor::load` will throw an error if a `null` path is passed.
+- Replaced deprecated code in `UserFrosting\Support\Repository\Repository`
+
 ## [4.3.0]
 - Dropping support for PHP 5.6 & 7.0
 - Updated Illuminate/Config to 5.8
@@ -34,6 +40,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 ## 4.0.0
 - Initial Release
 
+[4.3.1]: https://github.com/userfrosting/support/compare/4.3.0...4.3.1
 [4.3.0]: https://github.com/userfrosting/support/compare/4.2.1...4.3.0
 [4.2.1]: https://github.com/userfrosting/support/compare/4.2.0...4.2.1
 [4.2.0]: https://github.com/userfrosting/support/compare/4.1.3...4.2.0
diff --git a/composer.json b/composer.json
index 99377eb..42eb4bb 100644
--- a/composer.json
+++ b/composer.json
@@ -26,5 +26,10 @@
         "psr-4": {
             "UserFrosting\\Support\\": "src"
         }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "UserFrosting\\Support\\Tests\\": "tests"
+        }
     }
 }
diff --git a/src/DotenvEditor/DotenvEditor.php b/src/DotenvEditor/DotenvEditor.php
index d05c0bd..f682e8c 100644
--- a/src/DotenvEditor/DotenvEditor.php
+++ b/src/DotenvEditor/DotenvEditor.php
@@ -50,7 +50,7 @@ public function __construct($backupPath = '', $autoBackup = true)
     /**
      * Load file for working.
      *
-     * @param string|null $filePath          The file path
+     * @param string      $filePath          The file path
      * @param bool        $restoreIfNotFound Restore this file from other file if it's not found
      * @param string|null $restorePath       The file path you want to restore from
      *
@@ -58,6 +58,11 @@ public function __construct($backupPath = '', $autoBackup = true)
      */
     public function load($filePath = null, $restoreIfNotFound = false, $restorePath = null)
     {
+        //Fail if path is null to maintain compatibility with Jackiedo\DotenvEditor
+        if (is_null($filePath)) {
+            throw new \InvalidArgumentException('File path cannot be null');
+        }
+
         $this->resetContent();
         $this->filePath = $filePath;
 
@@ -68,7 +73,9 @@ public function load($filePath = null, $restoreIfNotFound = false, $restorePath
 
             return $this;
         } elseif ($restoreIfNotFound) {
-            return $this->restore($restorePath);
+            $this->restore($restorePath);
+
+            return $this;
         } else {
             return $this;
         }
diff --git a/src/Repository/Loader/ArrayFileLoader.php b/src/Repository/Loader/ArrayFileLoader.php
index 2723333..98c0657 100644
--- a/src/Repository/Loader/ArrayFileLoader.php
+++ b/src/Repository/Loader/ArrayFileLoader.php
@@ -18,9 +18,9 @@
 class ArrayFileLoader extends FileRepositoryLoader
 {
     /**
-     * @return array
+     * {@inheritdoc}
      */
-    protected function parseFile($path)
+    protected function parseFile(string $path): array
     {
         return require $path;
     }
diff --git a/src/Repository/Loader/FileRepositoryLoader.php b/src/Repository/Loader/FileRepositoryLoader.php
index e7d86fb..f65c799 100644
--- a/src/Repository/Loader/FileRepositoryLoader.php
+++ b/src/Repository/Loader/FileRepositoryLoader.php
@@ -20,7 +20,7 @@
 abstract class FileRepositoryLoader
 {
     /**
-     * @var array An array of paths to ultimately load the data from.
+     * @var string[] An array of paths to ultimately load the data from.
      */
     protected $paths = [];
 
@@ -39,18 +39,18 @@ public function __construct($paths)
      *
      * @param string $path
      *
-     * @return array
+     * @return mixed[]
      */
-    abstract protected function parseFile($path);
+    abstract protected function parseFile(string $path): array;
 
     /**
      * Fetch and recursively merge in content from all file paths.
      *
      * @param bool $skipMissing
      *
-     * @return array
+     * @return string[]
      */
-    public function load($skipMissing = true)
+    public function load(bool $skipMissing = true): array
     {
         $result = [];
 
@@ -70,9 +70,9 @@ public function load($skipMissing = true)
      *
      * @throws FileNotFoundException
      *
-     * @return array
+     * @return mixed[]
      */
-    public function loadFile($path, $skipMissing = true)
+    public function loadFile(string $path, $skipMissing = true): array
     {
         if (!file_exists($path)) {
             if ($skipMissing) {
@@ -97,7 +97,7 @@ public function loadFile($path, $skipMissing = true)
      *
      * @return bool
      */
-    protected function isReadable($path)
+    protected function isReadable(string $path): bool
     {
         return is_readable($path);
     }
@@ -107,7 +107,7 @@ protected function isReadable($path)
      *
      * @param string $path
      */
-    public function addPath($path)
+    public function addPath(string $path): self
     {
         $this->paths[] = rtrim($path, '/\\');
 
@@ -119,7 +119,7 @@ public function addPath($path)
      *
      * @param string $path
      */
-    public function prependPath($path)
+    public function prependPath($path): self
     {
         array_unshift($this->paths, rtrim($path, '/\\'));
 
@@ -131,7 +131,7 @@ public function prependPath($path)
      *
      * @param string|string[] $paths
      */
-    public function setPaths($paths)
+    public function setPaths($paths): self
     {
         if (!is_array($paths)) {
             $paths = [$paths];
@@ -149,9 +149,9 @@ public function setPaths($paths)
     /**
      * Return a list of all file paths.
      *
-     * @return array
+     * @return string[]
      */
-    public function getPaths()
+    public function getPaths(): array
     {
         return $this->paths;
     }
diff --git a/src/Repository/Loader/YamlFileLoader.php b/src/Repository/Loader/YamlFileLoader.php
index e7ba566..0cc10b3 100644
--- a/src/Repository/Loader/YamlFileLoader.php
+++ b/src/Repository/Loader/YamlFileLoader.php
@@ -25,7 +25,7 @@ class YamlFileLoader extends FileRepositoryLoader
     /**
      * {@inheritdoc}
      */
-    protected function parseFile($path)
+    protected function parseFile(string $path): array
     {
         $doc = $this->fileGetContents($path);
         if ($doc === false) {
@@ -42,6 +42,11 @@ protected function parseFile($path)
             }
         }
 
+        // In case `Yaml::parse` returns empty data/file
+        if (is_null($result)) {
+            return [];
+        }
+
         return $result;
     }
 
@@ -50,9 +55,9 @@ protected function parseFile($path)
      *
      * @param string $path
      *
-     * @return string|bool
+     * @return string|false
      */
-    protected function fileGetContents($path)
+    protected function fileGetContents(string $path)
     {
         return file_get_contents($path);
     }
diff --git a/src/Repository/PathBuilder/PathBuilder.php b/src/Repository/PathBuilder/PathBuilder.php
index 0577e66..bd1b59b 100644
--- a/src/Repository/PathBuilder/PathBuilder.php
+++ b/src/Repository/PathBuilder/PathBuilder.php
@@ -35,7 +35,7 @@ abstract class PathBuilder
      * @param ResourceLocatorInterface $locator
      * @param string                   $uri
      */
-    public function __construct(ResourceLocatorInterface $locator, $uri)
+    public function __construct(ResourceLocatorInterface $locator, string $uri)
     {
         $this->locator = $locator;
         $this->uri = $uri;
@@ -46,5 +46,5 @@ public function __construct(ResourceLocatorInterface $locator, $uri)
      *
      * @return array
      */
-    abstract public function buildPaths();
+    abstract public function buildPaths(): array;
 }
diff --git a/src/Repository/PathBuilder/SimpleGlobBuilder.php b/src/Repository/PathBuilder/SimpleGlobBuilder.php
index 01b7c8a..d38d3b5 100644
--- a/src/Repository/PathBuilder/SimpleGlobBuilder.php
+++ b/src/Repository/PathBuilder/SimpleGlobBuilder.php
@@ -20,9 +20,11 @@ class SimpleGlobBuilder extends PathBuilder
     /**
      * Glob together all file paths in each search path from the locator.
      *
+     * @param string $extension (default 'php')
+     *
      * @return array
      */
-    public function buildPaths($extension = 'php')
+    public function buildPaths(string $extension = 'php'): array
     {
         // Get all paths from the locator that match the uri.
         // Put them in reverse order to allow later files to override earlier files.
diff --git a/src/Repository/PathBuilder/StreamPathBuilder.php b/src/Repository/PathBuilder/StreamPathBuilder.php
index 83975b7..7130b3a 100644
--- a/src/Repository/PathBuilder/StreamPathBuilder.php
+++ b/src/Repository/PathBuilder/StreamPathBuilder.php
@@ -22,7 +22,7 @@ class StreamPathBuilder extends PathBuilder
      *
      * @return array
      */
-    public function buildPaths()
+    public function buildPaths(): array
     {
         // Get all paths from the locator that match the uri.
         // Put them in reverse order to allow later files to override earlier files.
diff --git a/src/Repository/Repository.php b/src/Repository/Repository.php
index 97229fa..fcbaf41 100644
--- a/src/Repository/Repository.php
+++ b/src/Repository/Repository.php
@@ -11,6 +11,7 @@
 namespace UserFrosting\Support\Repository;
 
 use Illuminate\Config\Repository as IlluminateRepository;
+use Illuminate\Support\Arr;
 use UserFrosting\Support\Util\Util;
 
 /**
@@ -32,9 +33,9 @@ class Repository extends IlluminateRepository
      * @param string|null $key
      * @param mixed       $items
      */
-    public function mergeItems($key, $items)
+    public function mergeItems(?string $key, $items): self
     {
-        $targetValues = array_get($this->items, $key);
+        $targetValues = Arr::get($this->items, $key);
 
         if (is_array($targetValues)) {
             $modifiedValues = array_replace_recursive($targetValues, $items);
@@ -42,7 +43,7 @@ public function mergeItems($key, $items)
             $modifiedValues = $items;
         }
 
-        array_set($this->items, $key, $modifiedValues);
+        Arr::set($this->items, $key, $modifiedValues);
 
         return $this;
     }
@@ -50,7 +51,7 @@ public function mergeItems($key, $items)
     /**
      * Get the specified configuration value, recursively removing all null values.
      *
-     * @param string $key
+     * @param string|array|null $key
      *
      * @return mixed
      */
diff --git a/src/Util/Util.php b/src/Util/Util.php
index cfbbde1..c4cbeac 100644
--- a/src/Util/Util.php
+++ b/src/Util/Util.php
@@ -111,7 +111,7 @@ public static function stripPrefix($str, $prefix = '')
      *
      * @param string|array $patterns
      * @param string       $subject
-     * @param array        &$matches
+     * @param array        $matches
      * @param string       $delimiter
      * @param int          $flags
      * @param int          $offset
diff --git a/tests/DotenvEditor/DotenvEditorTest.php b/tests/DotenvEditor/DotenvEditorTest.php
index 044325f..6f04333 100644
--- a/tests/DotenvEditor/DotenvEditorTest.php
+++ b/tests/DotenvEditor/DotenvEditorTest.php
@@ -8,6 +8,8 @@
  * @license   https://github.com/userfrosting/support/blob/master/LICENSE.md (MIT License)
  */
 
+namespace UserFrosting\Support\Tests\DotenvEditor;
+
 use PHPUnit\Framework\TestCase;
 use UserFrosting\Support\DotenvEditor\DotenvEditor;
 
@@ -73,6 +75,16 @@ public function testLoadPathNotExist()
         $this->assertEquals($editor, $result);
     }
 
+    /**
+     * @depends testConstructor
+     */
+    public function testLoadPathIsNull()
+    {
+        $editor = new DotenvEditor($this->basePath.'.env-backups/');
+        $this->expectException(\InvalidArgumentException::class);
+        $result = $editor->load();
+    }
+
     /**
      * @depends testConstructor
      */
diff --git a/tests/Exception/HttpExceptionTest.php b/tests/Exception/HttpExceptionTest.php
index 527212f..e16c67f 100644
--- a/tests/Exception/HttpExceptionTest.php
+++ b/tests/Exception/HttpExceptionTest.php
@@ -8,6 +8,8 @@
  * @license   https://github.com/userfrosting/support/blob/master/LICENSE.md (MIT License)
  */
 
+namespace UserFrosting\Support\Tests\Exception;
+
 use PHPUnit\Framework\TestCase;
 use UserFrosting\Support\Exception\HttpException;
 use UserFrosting\Support\Message\UserMessage;
diff --git a/tests/Repository/PathBuilderTest.php b/tests/Repository/PathBuilderTest.php
index 020c04c..69e1344 100644
--- a/tests/Repository/PathBuilderTest.php
+++ b/tests/Repository/PathBuilderTest.php
@@ -8,6 +8,8 @@
  * @license   https://github.com/userfrosting/support/blob/master/LICENSE.md (MIT License)
  */
 
+namespace UserFrosting\Support\Tests\Repository;
+
 use PHPUnit\Framework\TestCase;
 use UserFrosting\Support\Repository\PathBuilder\SimpleGlobBuilder;
 use UserFrosting\Support\Repository\PathBuilder\StreamPathBuilder;
diff --git a/tests/Repository/RepositoryLoaderTest.php b/tests/Repository/RepositoryLoaderTest.php
index 66b9bee..2f91cbb 100644
--- a/tests/Repository/RepositoryLoaderTest.php
+++ b/tests/Repository/RepositoryLoaderTest.php
@@ -8,6 +8,8 @@
  * @license   https://github.com/userfrosting/support/blob/master/LICENSE.md (MIT License)
  */
 
+namespace UserFrosting\Support\Tests\Repository;
+
 use PHPUnit\Framework\TestCase;
 use UserFrosting\Support\Exception\FileNotFoundException;
 use UserFrosting\Support\Exception\JsonException;
@@ -188,6 +190,62 @@ public function testYamlFileLoaderWithFalseFileContent()
         $data = $loader->load();
     }
 
+    /**
+     * Make sure an empty file doesn't mess up by returning null.
+     *
+     * @depends testYamlFileLoader
+     * @depends testYamlFileLoaderWithStringPath
+     */
+    public function testYamlFileLoaderWithNoFileContent()
+    {
+        $loader = new YamlFileLoader(__DIR__.'/data/core/owls/empty.yaml');
+
+        // Act
+        $data = $loader->load();
+
+        $this->assertEquals([], $data);
+    }
+
+    /**
+     * Make sure an empty file doesn't mess up by returning null.
+     *
+     * @depends testYamlFileLoaderWithNoFileContent
+     */
+    public function testYamlFileLoaderWithNoFileContentOnFirstFile()
+    {
+        $loader = new YamlFileLoader([
+            __DIR__.'/data/core/owls/empty.yaml',
+            __DIR__.'/data/core/owls/tyto.yaml',
+        ]);
+
+        // Act
+        $data = $loader->load();
+
+        $this->assertEquals([
+            'plumage' => 'floofy',
+        ], $data);
+    }
+
+    /**
+     * Make sure an empty file doesn't mess up by returning null.
+     *
+     * @depends testYamlFileLoaderWithNoFileContent
+     */
+    public function testYamlFileLoaderWithNoFileContentOnSecondFile()
+    {
+        $loader = new YamlFileLoader([
+            __DIR__.'/data/core/owls/tyto.yaml',
+            __DIR__.'/data/core/owls/empty.yaml',
+        ]);
+
+        // Act
+        $data = $loader->load();
+
+        $this->assertEquals([
+            'plumage' => 'floofy',
+        ], $data);
+    }
+
     /**
      * @depends testYamlFileLoader
      */
diff --git a/tests/Repository/RepositoryTest.php b/tests/Repository/RepositoryTest.php
index 559887b..12d74cf 100644
--- a/tests/Repository/RepositoryTest.php
+++ b/tests/Repository/RepositoryTest.php
@@ -8,6 +8,8 @@
  * @license   https://github.com/userfrosting/support/blob/master/LICENSE.md (MIT License)
  */
 
+namespace UserFrosting\Support\Tests\Repository;
+
 use PHPUnit\Framework\TestCase;
 use UserFrosting\Support\Repository\Repository;
 
@@ -65,6 +67,23 @@ public function testGetDefinedWithString()
         $this->assertEquals(4, $defined);
     }
 
+    /**
+     * @depends testGetDefined
+     */
+    public function testGetDefinedWithArray()
+    {
+        $repo = new Repository($this->data);
+
+        $defined = $repo->getDefined(['chicks', 'voles']);
+
+        $this->assertEquals([
+            'chicks' => 4,
+            'voles'  => [
+                'caught' => 8,
+            ],
+        ], $defined);
+    }
+
     /**
      * @depends testGetDefinedWithString
      */
@@ -95,4 +114,21 @@ public function testMergeItemsWithArray()
 
         $this->assertEquals($newData, $defined);
     }
+
+    /**
+     * @depends testGetDefinedWithString
+     */
+    public function testMergeItemsWithNull()
+    {
+        $repo = new Repository($this->data);
+
+        $newData = [
+            'foo'    => 'bar',
+        ];
+
+        $repo->mergeItems(null, $newData);
+        $defined = $repo->getDefined('foo');
+
+        $this->assertEquals('bar', $defined);
+    }
 }
diff --git a/tests/Repository/data/core/owls/empty.yaml b/tests/Repository/data/core/owls/empty.yaml
new file mode 100644
index 0000000..e69de29
diff --git a/tests/Util/UtilTest.php b/tests/Util/UtilTest.php
index ef8e275..3d83d57 100644
--- a/tests/Util/UtilTest.php
+++ b/tests/Util/UtilTest.php
@@ -8,6 +8,8 @@
  * @license   https://github.com/userfrosting/support/blob/master/LICENSE.md (MIT License)
  */
 
+namespace UserFrosting\Support\Tests\Util;
+
 use PHPUnit\Framework\TestCase;
 use UserFrosting\Support\Util\Util;