diff --git a/composer.json b/composer.json
index e93a853..1d0c2f3 100644
--- a/composer.json
+++ b/composer.json
@@ -3,8 +3,8 @@
     "description": "Load guzzle service description from various file formats",
     "require": {
         "php": ">=5.5.0",
-        "symfony/config": "~3.0",
-        "symfony/yaml": "~3.0"
+        "symfony/config": ">=4",
+        "symfony/yaml": ">=4"
     },
     "license": "MIT",
     "authors": [
diff --git a/composer.lock b/composer.lock
index 2e9db00..945ca75 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1,34 +1,47 @@
 {
     "_readme": [
         "This file locks the dependencies of your project to a known state",
-        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "hash": "950a6c7017df36346b2daebfd6a55cf7",
-    "content-hash": "b19a782dc303a22631422c69ca828fa0",
+    "content-hash": "f49a6d02fdcb7e784e02073c453ec028",
     "packages": [
         {
             "name": "symfony/config",
-            "version": "v3.0.1",
+            "version": "v4.3.5",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/config.git",
-                "reference": "58680a6516a457a6c65044fe33586c4a81fdff01"
+                "reference": "0acb26407a9e1a64a275142f0ae5e36436342720"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/config/zipball/58680a6516a457a6c65044fe33586c4a81fdff01",
-                "reference": "58680a6516a457a6c65044fe33586c4a81fdff01",
+                "url": "https://api.github.com/repos/symfony/config/zipball/0acb26407a9e1a64a275142f0ae5e36436342720",
+                "reference": "0acb26407a9e1a64a275142f0ae5e36436342720",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.5.9",
-                "symfony/filesystem": "~2.8|~3.0"
+                "php": "^7.1.3",
+                "symfony/filesystem": "~3.4|~4.0",
+                "symfony/polyfill-ctype": "~1.8"
+            },
+            "conflict": {
+                "symfony/finder": "<3.4"
+            },
+            "require-dev": {
+                "symfony/dependency-injection": "~3.4|~4.0",
+                "symfony/event-dispatcher": "~3.4|~4.0",
+                "symfony/finder": "~3.4|~4.0",
+                "symfony/messenger": "~4.1",
+                "symfony/yaml": "~3.4|~4.0"
+            },
+            "suggest": {
+                "symfony/yaml": "To use the yaml reference dumper"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "4.3-dev"
                 }
             },
             "autoload": {
@@ -55,29 +68,30 @@
             ],
             "description": "Symfony Config Component",
             "homepage": "https://symfony.com",
-            "time": "2015-12-26 13:39:53"
+            "time": "2019-09-19T15:51:53+00:00"
         },
         {
             "name": "symfony/filesystem",
-            "version": "v3.0.1",
+            "version": "v4.3.5",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/filesystem.git",
-                "reference": "c2e59d11dccd135dc8f00ee97f34fe1de842e70c"
+                "reference": "9abbb7ef96a51f4d7e69627bc6f63307994e4263"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/filesystem/zipball/c2e59d11dccd135dc8f00ee97f34fe1de842e70c",
-                "reference": "c2e59d11dccd135dc8f00ee97f34fe1de842e70c",
+                "url": "https://api.github.com/repos/symfony/filesystem/zipball/9abbb7ef96a51f4d7e69627bc6f63307994e4263",
+                "reference": "9abbb7ef96a51f4d7e69627bc6f63307994e4263",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.5.9"
+                "php": "^7.1.3",
+                "symfony/polyfill-ctype": "~1.8"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "4.3-dev"
                 }
             },
             "autoload": {
@@ -104,29 +118,97 @@
             ],
             "description": "Symfony Filesystem Component",
             "homepage": "https://symfony.com",
-            "time": "2015-12-22 10:39:06"
+            "time": "2019-08-20T14:07:54+00:00"
+        },
+        {
+            "name": "symfony/polyfill-ctype",
+            "version": "v1.12.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-ctype.git",
+                "reference": "550ebaac289296ce228a706d0867afc34687e3f4"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-ctype/zipball/550ebaac289296ce228a706d0867afc34687e3f4",
+                "reference": "550ebaac289296ce228a706d0867afc34687e3f4",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "suggest": {
+                "ext-ctype": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.12-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Ctype\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Gert de Pagter",
+                    "email": "BackEndTea@gmail.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill for ctype functions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "ctype",
+                "polyfill",
+                "portable"
+            ],
+            "time": "2019-08-06T08:03:45+00:00"
         },
         {
             "name": "symfony/yaml",
-            "version": "v3.0.1",
+            "version": "v4.3.5",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/yaml.git",
-                "reference": "3df409958a646dad2bc5046c3fb671ee24a1a691"
+                "reference": "41e16350a2a1c7383c4735aa2f9fce74cf3d1178"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/yaml/zipball/3df409958a646dad2bc5046c3fb671ee24a1a691",
-                "reference": "3df409958a646dad2bc5046c3fb671ee24a1a691",
+                "url": "https://api.github.com/repos/symfony/yaml/zipball/41e16350a2a1c7383c4735aa2f9fce74cf3d1178",
+                "reference": "41e16350a2a1c7383c4735aa2f9fce74cf3d1178",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.5.9"
+                "php": "^7.1.3",
+                "symfony/polyfill-ctype": "~1.8"
+            },
+            "conflict": {
+                "symfony/console": "<3.4"
+            },
+            "require-dev": {
+                "symfony/console": "~3.4|~4.0"
+            },
+            "suggest": {
+                "symfony/console": "For validating YAML files using the lint command"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "4.3-dev"
                 }
             },
             "autoload": {
@@ -153,7 +235,7 @@
             ],
             "description": "Symfony Yaml Component",
             "homepage": "https://symfony.com",
-            "time": "2015-12-26 13:39:53"
+            "time": "2019-09-11T15:41:19+00:00"
         }
     ],
     "packages-dev": [],