diff --git a/.github/workflows/dependency-updates.yml b/.github/workflows/dependency-updates.yml
index dc1824f1..b5f907e9 100644
--- a/.github/workflows/dependency-updates.yml
+++ b/.github/workflows/dependency-updates.yml
@@ -13,7 +13,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: shivammathur/setup-php@v2
       with:
-        php-version: 8.2
+        php-version: 8.3
         extensions: apcu
     - name: Run dependency update script
       run: |
diff --git a/.github/workflows/lint-php.yml b/.github/workflows/lint-php.yml
index 41ed1874..2381300b 100644
--- a/.github/workflows/lint-php.yml
+++ b/.github/workflows/lint-php.yml
@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-versions: [ "8.2" ]
+        php-versions: [ "8.3" ]
 
     name: php-lint
 
diff --git a/.github/workflows/php-deprecation-detector.yml b/.github/workflows/php-deprecation-detector.yml
index 44e2236c..6d88d3c6 100644
--- a/.github/workflows/php-deprecation-detector.yml
+++ b/.github/workflows/php-deprecation-detector.yml
@@ -17,10 +17,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Set up php8.2
+      - name: Set up php
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.2
+          php-version: 8.3
           extensions: apcu
           coverage: none
 
diff --git a/.github/workflows/psalm-update-baseline.yml b/.github/workflows/psalm-update-baseline.yml
index 266763e3..7ac04412 100644
--- a/.github/workflows/psalm-update-baseline.yml
+++ b/.github/workflows/psalm-update-baseline.yml
@@ -12,10 +12,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Set up php8.2
+      - name: Set up php
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.2
+          php-version: 8.3
           extensions: apcu
           coverage: none
 
diff --git a/.github/workflows/psalm.yml b/.github/workflows/psalm.yml
index 7ec63d28..de622279 100644
--- a/.github/workflows/psalm.yml
+++ b/.github/workflows/psalm.yml
@@ -31,7 +31,7 @@ jobs:
       - name: Set up php
         uses: shivammathur/setup-php@c5fc0d8281aba02c7fda07d3a70cc5371548067d # v2
         with:
-          php-version: 8.2
+          php-version: 8.3
           extensions: apcu
           coverage: none
           ini-file: development
diff --git a/.github/workflows/twig-lint.yml b/.github/workflows/twig-lint.yml
index 1a185d17..34d6afb6 100644
--- a/.github/workflows/twig-lint.yml
+++ b/.github/workflows/twig-lint.yml
@@ -29,7 +29,7 @@ jobs:
       - name: Set up php ${{ matrix.php-versions }}
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.2
+          php-version: 8.3
           extensions: apcu
           coverage: none
 
diff --git a/Containers/mastercontainer/Dockerfile b/Containers/mastercontainer/Dockerfile
index 0ad9eb39..7abe7348 100644
--- a/Containers/mastercontainer/Dockerfile
+++ b/Containers/mastercontainer/Dockerfile
@@ -5,8 +5,8 @@ FROM docker:25.0.3-cli as docker
 # Caddy is a requirement
 FROM caddy:2.7.6-alpine as caddy
 
-# From https://github.com/docker-library/php/blob/master/8.2/alpine3.19/fpm/Dockerfile
-FROM php:8.2.16-fpm-alpine3.19
+# From https://github.com/docker-library/php/blob/master/8.3/alpine3.19/fpm/Dockerfile
+FROM php:8.3.3-fpm-alpine3.19
 
 EXPOSE 80
 EXPOSE 8080
diff --git a/php/composer.json b/php/composer.json
index 32488056..7dd9c8c3 100644
--- a/php/composer.json
+++ b/php/composer.json
@@ -5,7 +5,7 @@
         }
     },
     "require": {
-        "php": "8.2.*",
+        "php": "8.3.*",
         "ext-json": "*",
         "ext-sodium": "*",
         "ext-curl": "*",
@@ -22,6 +22,6 @@
 		"psalm": "psalm --threads=1",
 		"psalm:update-baseline": "psalm --threads=1 --update-baseline",
 		"lint": "find . -name \\*.php -not -path './vendor/*' -exec php -l {} \\;",
-		"php-deprecation-detector": "find . -name \\*.php -not -path './vendor/*' -exec phpdd scan {} -n -t 8.2 \\;"
+		"php-deprecation-detector": "find . -name \\*.php -not -path './vendor/*' -exec phpdd scan {} -n -t 8.3 \\;"
 	}
 }
diff --git a/php/composer.lock b/php/composer.lock
index f36bb64b..f111306c 100644
--- a/php/composer.lock
+++ b/php/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": "b0074cfbf6b5cde6d6d2207286ad2e85",
+    "content-hash": "4dcdd3b6df3f2041895d4db74bd45102",
     "packages": [
         {
             "name": "guzzlehttp/guzzle",
@@ -1148,16 +1148,16 @@
         },
         {
             "name": "slim/slim",
-            "version": "4.12.0",
+            "version": "4.13.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/slimphp/Slim.git",
-                "reference": "e9e99c2b24398b967841c6c4c3048622cc7e2b18"
+                "reference": "038fd5713d5a41636fdff0e8dcceedecdd17fc17"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/slimphp/Slim/zipball/e9e99c2b24398b967841c6c4c3048622cc7e2b18",
-                "reference": "e9e99c2b24398b967841c6c4c3048622cc7e2b18",
+                "url": "https://api.github.com/repos/slimphp/Slim/zipball/038fd5713d5a41636fdff0e8dcceedecdd17fc17",
+                "reference": "038fd5713d5a41636fdff0e8dcceedecdd17fc17",
                 "shasum": ""
             },
             "require": {
@@ -1166,7 +1166,7 @@
                 "php": "^7.4 || ^8.0",
                 "psr/container": "^1.0 || ^2.0",
                 "psr/http-factory": "^1.0",
-                "psr/http-message": "^1.1",
+                "psr/http-message": "^1.1 || ^2.0",
                 "psr/http-server-handler": "^1.0",
                 "psr/http-server-middleware": "^1.0",
                 "psr/log": "^1.1 || ^2.0 || ^3.0"
@@ -1174,19 +1174,19 @@
             "require-dev": {
                 "adriansuter/php-autoload-override": "^1.4",
                 "ext-simplexml": "*",
-                "guzzlehttp/psr7": "^2.5",
+                "guzzlehttp/psr7": "^2.6",
                 "httpsoft/http-message": "^1.1",
                 "httpsoft/http-server-request": "^1.1",
-                "laminas/laminas-diactoros": "^2.17",
+                "laminas/laminas-diactoros": "^2.17 || ^3",
                 "nyholm/psr7": "^1.8",
-                "nyholm/psr7-server": "^1.0",
-                "phpspec/prophecy": "^1.17",
-                "phpspec/prophecy-phpunit": "^2.0",
+                "nyholm/psr7-server": "^1.1",
+                "phpspec/prophecy": "^1.19",
+                "phpspec/prophecy-phpunit": "^2.1",
                 "phpstan/phpstan": "^1.10",
                 "phpunit/phpunit": "^9.6",
                 "slim/http": "^1.3",
                 "slim/psr7": "^1.6",
-                "squizlabs/php_codesniffer": "^3.7"
+                "squizlabs/php_codesniffer": "^3.9"
             },
             "suggest": {
                 "ext-simplexml": "Needed to support XML format in BodyParsingMiddleware",
@@ -1259,7 +1259,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2023-07-23T04:54:29+00:00"
+            "time": "2024-03-03T21:25:30+00:00"
         },
         {
             "name": "slim/twig-view",
@@ -1788,7 +1788,7 @@
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": {
-        "php": "8.2.*",
+        "php": "8.3.*",
         "ext-json": "*",
         "ext-sodium": "*",
         "ext-curl": "*",