diff --git a/01-simple-application/web-application/composer.json b/01-simple-application/web-application/composer.json
index 76ce994..5be5fc1 100644
--- a/01-simple-application/web-application/composer.json
+++ b/01-simple-application/web-application/composer.json
@@ -10,7 +10,7 @@
     "require": {
         "slim/slim": "4.8.0",
         "guzzlehttp/guzzle": "7.3.0",
-        "guzzlehttp/psr7": "1.8.1",
+        "guzzlehttp/psr7": "1.8.4",
         "http-interop/http-factory-guzzle": "1.2.0"
     }
 }
diff --git a/01-simple-application/web-application/composer.lock b/01-simple-application/web-application/composer.lock
index bbc8d86..2e2be68 100644
--- a/01-simple-application/web-application/composer.lock
+++ b/01-simple-application/web-application/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "b96125d938ff09ba0f44c6bec05760c7",
+    "content-hash": "5cecff9648ddd72d74ad7452a1bc0926",
     "packages": [
         {
             "name": "guzzlehttp/guzzle",
@@ -166,16 +166,16 @@
         },
         {
             "name": "guzzlehttp/psr7",
-            "version": "1.8.1",
+            "version": "1.8.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/guzzle/psr7.git",
-                "reference": "35ea11d335fd638b5882ff1725228b3d35496ab1"
+                "reference": "902db15a551a4a415e732b622282e21ce1b508b4"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/psr7/zipball/35ea11d335fd638b5882ff1725228b3d35496ab1",
-                "reference": "35ea11d335fd638b5882ff1725228b3d35496ab1",
+                "url": "https://api.github.com/repos/guzzle/psr7/zipball/902db15a551a4a415e732b622282e21ce1b508b4",
+                "reference": "902db15a551a4a415e732b622282e21ce1b508b4",
                 "shasum": ""
             },
             "require": {
@@ -200,25 +200,46 @@
                 }
             },
             "autoload": {
-                "psr-4": {
-                    "GuzzleHttp\\Psr7\\": "src/"
-                },
                 "files": [
                     "src/functions_include.php"
-                ]
+                ],
+                "psr-4": {
+                    "GuzzleHttp\\Psr7\\": "src/"
+                }
             },
             "notification-url": "https://packagist.org/downloads/",
             "license": [
                 "MIT"
             ],
             "authors": [
+                {
+                    "name": "Graham Campbell",
+                    "email": "hello@gjcampbell.co.uk",
+                    "homepage": "https://github.com/GrahamCampbell"
+                },
                 {
                     "name": "Michael Dowling",
                     "email": "mtdowling@gmail.com",
                     "homepage": "https://github.com/mtdowling"
                 },
+                {
+                    "name": "George Mponos",
+                    "email": "gmponos@gmail.com",
+                    "homepage": "https://github.com/gmponos"
+                },
+                {
+                    "name": "Tobias Nyholm",
+                    "email": "tobias.nyholm@gmail.com",
+                    "homepage": "https://github.com/Nyholm"
+                },
+                {
+                    "name": "Márk Sági-Kazár",
+                    "email": "mark.sagikazar@gmail.com",
+                    "homepage": "https://github.com/sagikazarmark"
+                },
                 {
                     "name": "Tobias Schultze",
+                    "email": "webmaster@tubo-world.de",
                     "homepage": "https://github.com/Tobion"
                 }
             ],
@@ -235,9 +256,23 @@
             ],
             "support": {
                 "issues": "https://github.com/guzzle/psr7/issues",
-                "source": "https://github.com/guzzle/psr7/tree/1.8.1"
+                "source": "https://github.com/guzzle/psr7/tree/1.8.4"
             },
-            "time": "2021-03-21T16:25:00+00:00"
+            "funding": [
+                {
+                    "url": "https://github.com/GrahamCampbell",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/Nyholm",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/guzzlehttp/psr7",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2022-03-20T13:44:44+00:00"
         },
         {
             "name": "http-interop/http-factory-guzzle",
@@ -891,5 +926,5 @@
     "prefer-lowest": false,
     "platform": [],
     "platform-dev": [],
-    "plugin-api-version": "2.1.0"
+    "plugin-api-version": "2.2.0"
 }