diff --git a/.travis.yml b/.travis.yml
index 454dd54..a1bb847 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,6 @@
 language: php
 
 php:
-    - 5.5
-    - 5.6
     - 7.0
 
 sudo: true
diff --git a/composer.json b/composer.json
index f392f0e..e7edc48 100644
--- a/composer.json
+++ b/composer.json
@@ -1,16 +1,17 @@
 {
     "name": "samburns/config-file-parser",
 
-    "version": "1.0.0",
+    "version": "2.0.0",
 
     "license": "MIT",
 
     "require": {
+        "php": "^7.0.0",
         "symfony/yaml": ">=2.8.0 <4.0.0"
     },
 
     "require-dev": {
-        "phpunit/phpunit":        ">=4.8.0 <5.1.0",
+        "phpunit/phpunit":        "~5.1.0",
         "satooshi/php-coveralls": "~0.1.0"
     },
 
diff --git a/src/SamBurns/ConfigFileParser/ConfigFileParser.php b/src/SamBurns/ConfigFileParser/ConfigFileParser.php
index 6d9b418..eb40335 100644
--- a/src/SamBurns/ConfigFileParser/ConfigFileParser.php
+++ b/src/SamBurns/ConfigFileParser/ConfigFileParser.php
@@ -16,11 +16,8 @@ class ConfigFileParser
     /**
      * @throws FileFormatNotParsable
      * @throws FileNotReadable
-     *
-     * @param $pathToFile
-     * @return array
      */
-    public function parseConfigFile($pathToFile)
+    public function parseConfigFile(string $pathToFile): array
     {
         $file = $this->getParsableFileFromPath($pathToFile);
         return $file->toArray();
@@ -28,11 +25,8 @@ public function parseConfigFile($pathToFile)
 
     /**
      * @throws FileFormatNotParsable
-     *
-     * @param string $pathToFile
-     * @return ParsableFile
      */
-    private function getParsableFileFromPath($pathToFile)
+    private function getParsableFileFromPath(string $pathToFile): ParsableFile
     {
         $fileExtension = pathinfo($pathToFile)['extension'];
 
diff --git a/src/SamBurns/ConfigFileParser/Exception/FileFormatNotParsable.php b/src/SamBurns/ConfigFileParser/Exception/FileFormatNotParsable.php
index ddd6a76..f45fbbb 100644
--- a/src/SamBurns/ConfigFileParser/Exception/FileFormatNotParsable.php
+++ b/src/SamBurns/ConfigFileParser/Exception/FileFormatNotParsable.php
@@ -3,11 +3,7 @@
 
 class FileFormatNotParsable extends \RuntimeException
 {
-    /**
-     * @param string $path
-     * @return FileFormatNotParsable
-     */
-    public static function constructWithFilePath($path)
+    public static function constructWithFilePath(string $path): FileFormatNotParsable
     {
         $message = 'Config file "' . $path . '" is not of a format that can be parsed. Try .ini, .php, .json, or .yml.';
         return new static($message);
diff --git a/src/SamBurns/ConfigFileParser/Exception/FileNotReadable.php b/src/SamBurns/ConfigFileParser/Exception/FileNotReadable.php
index eb58036..c5f8e60 100644
--- a/src/SamBurns/ConfigFileParser/Exception/FileNotReadable.php
+++ b/src/SamBurns/ConfigFileParser/Exception/FileNotReadable.php
@@ -3,11 +3,7 @@
 
 class FileNotReadable extends \RuntimeException
 {
-    /**
-     * @param string $path
-     * @return FileNotReadable
-     */
-    public static function constructWithPath($path)
+    public static function constructWithPath(string $path): FileNotReadable
     {
         $message = 'Config file "' . $path . '" could not be read';
         return new static($message);
diff --git a/src/SamBurns/ConfigFileParser/File/ParsableFile.php b/src/SamBurns/ConfigFileParser/File/ParsableFile.php
index 4d07535..61fae7a 100644
--- a/src/SamBurns/ConfigFileParser/File/ParsableFile.php
+++ b/src/SamBurns/ConfigFileParser/File/ParsableFile.php
@@ -3,8 +3,5 @@
 
 interface ParsableFile
 {
-    /**
-     * @return array
-     */
-    public function toArray();
+    public function toArray(): array;
 }
diff --git a/src/SamBurns/ConfigFileParser/File/ParsableFile/IniFile.php b/src/SamBurns/ConfigFileParser/File/ParsableFile/IniFile.php
index 1902f2f..6247478 100644
--- a/src/SamBurns/ConfigFileParser/File/ParsableFile/IniFile.php
+++ b/src/SamBurns/ConfigFileParser/File/ParsableFile/IniFile.php
@@ -12,20 +12,13 @@ class IniFile implements ParsableFile
     /** @var FileContentsRetriever */
     private $fileContentsRetriever;
 
-    /**
-     * @param string                $path
-     * @param FileContentsRetriever $fileContentsRetriever
-     */
-    public function __construct($path, FileContentsRetriever $fileContentsRetriever)
+    public function __construct(string $path, FileContentsRetriever $fileContentsRetriever)
     {
         $this->path = $path;
         $this->fileContentsRetriever = $fileContentsRetriever;
     }
 
-    /**
-     * @return array
-     */
-    public function toArray()
+    public function toArray(): array
     {
         $fileContents = $this->fileContentsRetriever->fileGetContents($this->path);
         return parse_ini_string($fileContents);
diff --git a/src/SamBurns/ConfigFileParser/File/ParsableFile/JsonFile.php b/src/SamBurns/ConfigFileParser/File/ParsableFile/JsonFile.php
index 0328435..8e4c108 100644
--- a/src/SamBurns/ConfigFileParser/File/ParsableFile/JsonFile.php
+++ b/src/SamBurns/ConfigFileParser/File/ParsableFile/JsonFile.php
@@ -12,20 +12,13 @@ class JsonFile implements ParsableFile
     /** @var FileContentsRetriever */
     private $fileContentsRetriever;
 
-    /**
-     * @param string                $path
-     * @param FileContentsRetriever $fileContentsRetriever
-     */
-    public function __construct($path, FileContentsRetriever $fileContentsRetriever)
+    public function __construct(string $path, FileContentsRetriever $fileContentsRetriever)
     {
         $this->path = $path;
         $this->fileContentsRetriever = $fileContentsRetriever;
     }
 
-    /**
-     * @return array
-     */
-    public function toArray()
+    public function toArray(): array
     {
         $fileContents = $this->fileContentsRetriever->fileGetContents($this->path);
         return json_decode($fileContents, true);
diff --git a/src/SamBurns/ConfigFileParser/File/ParsableFile/PhpArrayFile.php b/src/SamBurns/ConfigFileParser/File/ParsableFile/PhpArrayFile.php
index 0c0a5a7..b2cc4fb 100644
--- a/src/SamBurns/ConfigFileParser/File/ParsableFile/PhpArrayFile.php
+++ b/src/SamBurns/ConfigFileParser/File/ParsableFile/PhpArrayFile.php
@@ -8,18 +8,12 @@ class PhpArrayFile implements ParsableFile
     /** @var string */
     private $path;
 
-    /**
-     * @param string $path
-     */
-    public function __construct($path)
+    public function __construct(string $path)
     {
         $this->path = $path;
     }
 
-    /**
-     * @return array
-     */
-    public function toArray()
+    public function toArray(): array
     {
         return require $this->path;
     }
diff --git a/src/SamBurns/ConfigFileParser/File/ParsableFile/YamlFile.php b/src/SamBurns/ConfigFileParser/File/ParsableFile/YamlFile.php
index 6ea6906..7cecef0 100644
--- a/src/SamBurns/ConfigFileParser/File/ParsableFile/YamlFile.php
+++ b/src/SamBurns/ConfigFileParser/File/ParsableFile/YamlFile.php
@@ -16,22 +16,14 @@ class YamlFile implements ParsableFile
     /** @var YamlParser */
     private $yamlParser;
 
-    /**
-     * @param string                $path
-     * @param FileContentsRetriever $fileContentsRetriever
-     * @param YamlParser            $yamlParser
-     */
-    public function __construct($path, FileContentsRetriever $fileContentsRetriever, YamlParser $yamlParser)
+    public function __construct(string $path, FileContentsRetriever $fileContentsRetriever, YamlParser $yamlParser)
     {
         $this->path                  = $path;
         $this->fileContentsRetriever = $fileContentsRetriever;
         $this->yamlParser            = $yamlParser;
     }
 
-    /**
-     * @return array
-     */
-    public function toArray()
+    public function toArray(): array
     {
         $fileContents = $this->fileContentsRetriever->fileGetContents($this->path);
         return $this->yamlParser->parse($fileContents);
diff --git a/src/SamBurns/ConfigFileParser/FileReading/FileContentsRetriever.php b/src/SamBurns/ConfigFileParser/FileReading/FileContentsRetriever.php
index 0047f9b..06e2b46 100644
--- a/src/SamBurns/ConfigFileParser/FileReading/FileContentsRetriever.php
+++ b/src/SamBurns/ConfigFileParser/FileReading/FileContentsRetriever.php
@@ -7,11 +7,8 @@ class FileContentsRetriever
 {
     /**
      * @throws FileNotReadable
-     *
-     * @param string $path
-     * @return string
      */
-    public function fileGetContents($path)
+    public function fileGetContents(string $path): string
     {
         if (!is_readable($path)) {
             throw FileNotReadable::constructWithPath($path);
diff --git a/tests/phpunit/SamBurns/ConfigFileParser/Test/ReadingVariousFileFormatTest.php b/tests/phpunit/SamBurns/ConfigFileParser/Test/ReadingVariousFileFormatTest.php
index d5e3c16..9074971 100644
--- a/tests/phpunit/SamBurns/ConfigFileParser/Test/ReadingVariousFileFormatTest.php
+++ b/tests/phpunit/SamBurns/ConfigFileParser/Test/ReadingVariousFileFormatTest.php
@@ -25,7 +25,7 @@ public function testReadingFileContents($filename, $errorMessage)
         $this->assertEquals($expectedArray, $arrayReadFromFile, $errorMessage);
     }
 
-    public function provideFilenames()
+    public function provideFilenames(): array
     {
         return [
             ['config.ini',  'Error parsing .ini config file'],