diff --git a/.changes/nextrelease/8-deprecation.json b/.changes/nextrelease/8-deprecation.json
new file mode 100644
index 0000000000..c09f89631d
--- /dev/null
+++ b/.changes/nextrelease/8-deprecation.json
@@ -0,0 +1,7 @@
+[
+  {
+    "type": "feature",
+    "category": "",
+    "description": "Drops support for PHP runtimes 8.0.x and below.  Adds support for PHP 8.4."
+  }
+]
diff --git a/.github/workflows/docs-build.yml b/.github/workflows/docs-build.yml
index 4aba5c5f7c..c1e390612d 100644
--- a/.github/workflows/docs-build.yml
+++ b/.github/workflows/docs-build.yml
@@ -5,7 +5,7 @@ on:
       - master
 jobs:
   build_docs:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     strategy:
       matrix:
         php-versions: ['8.1']
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 0da2fbeab2..933f1edcc9 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   verify-no-models-changes:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     name: Check for model changes
     if: github.event_name == 'pull_request'
     steps:
@@ -30,11 +30,11 @@ jobs:
             exit 1
           fi
   run:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     strategy:
       #for each of the following versions of PHP, with and without --prefer-lowest
       matrix:
-        php-versions: ['7.2.5', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3']
+        php-versions: ['8.1', '8.2', '8.3', '8.4']
         composer-options: ['', '--prefer-lowest']
     #set the name for each job
     name: PHP ${{ matrix.php-versions }} ${{ matrix.composer-options }}
@@ -65,37 +65,32 @@ jobs:
     - name: Install dependencies
       run: composer update ${{ matrix.composer-options }} --no-interaction --prefer-source
 
-    #php 8.x requirements
-    - if: ${{ matrix.php-versions >= '8.0' && matrix.composer-options != '' }}
-      name: PHP 8.x
-      run: composer require --dev phpunit/phpunit "^9.5" --no-interaction --prefer-source --with-all-dependencies
-
     #php 8.1+ requirements
-    - if: ${{ matrix.php-versions >= '8.1' && matrix.composer-options != '' }}
-      name: PHP 8.1+
-      run: composer require --dev guzzlehttp/guzzle "^7.4.5" --no-interaction --prefer-source --with-all-dependencies
+    - name: PHP 8.1+ requirements
+      run: composer require --dev phpunit/phpunit "^9.5" guzzlehttp/guzzle "^7.4.5" --no-interaction --prefer-source --with-all-dependencies
 
     #run tests
     - name: Run test suite
       run: make test
 
     #static analysis
-    - if: ${{ matrix.php-versions < '8.0' && matrix.composer-options == '' }}
-      name: Static analysis
+    - name: Static analysis
+      with:
+        fetch-depth: 0
       run: |
-        composer require --dev nette/neon "^3.0"
-        composer require --dev phpstan/phpstan "0.12.45"
+        composer require --dev nette/neon "^3.4.4"
+        composer require --dev phpstan/phpstan "2.1.1"
         vendor/bin/phpstan analyse src
 
     #generate package
     - if:  ${{ matrix.composer-options == '' }}
       name: Package generation
       run: |
-        composer config platform.php 7.2.5
+        composer config platform.php 8.1
         composer update
         make package
 
     #generate code coverage
-    - if: ${{ (matrix.php-versions == '7.2.5' || matrix.php-versions == '8.0') && matrix.composer-options == '' }}
-      name: Code coverage
+    - if: ${{ matrix.composer-options == '' }}
+      name: Code Coverage
       run: bash <(curl -s https://codecov.io/bash)
diff --git a/composer.json b/composer.json
index bc03915aea..3e0e525a03 100644
--- a/composer.json
+++ b/composer.json
@@ -12,23 +12,23 @@
         }
     ],
     "support": {
-        "forum": "https://forums.aws.amazon.com/forum.jspa?forumID=80",
+        "forum": "https://github.com/aws/aws-sdk-php/discussions",
         "issues": "https://github.com/aws/aws-sdk-php/issues"
     },
     "require": {
-        "php": ">=7.2.5",
-        "guzzlehttp/guzzle": "^6.5.8 || ^7.4.5",
-        "guzzlehttp/psr7": "^1.9.1 || ^2.4.5",
-        "guzzlehttp/promises": "^1.4.0 || ^2.0",
+        "php": ">=8.1",
+        "guzzlehttp/guzzle": "^7.4.5",
+        "guzzlehttp/psr7": "^2.4.5",
+        "guzzlehttp/promises": "^2.0",
         "mtdowling/jmespath.php": "^2.6",
         "ext-pcre": "*",
         "ext-json": "*",
         "ext-simplexml": "*",
         "aws/aws-crt-php": "^1.2.3",
-        "psr/http-message": "^1.0 || ^2.0"
+        "psr/http-message": "^2.0"
     },
     "require-dev": {
-        "composer/composer" : "^1.10.22",
+        "composer/composer" : "^2.2",
         "ext-openssl": "*",
         "ext-dom": "*",
         "ext-pcntl": "*",
@@ -37,13 +37,12 @@
         "behat/behat": "~3.0",
         "doctrine/cache": "~1.4",
         "aws/aws-php-sns-message-validator": "~1.0",
-        "nette/neon": "^2.3",
         "andrewsville/php-token-reflection": "^1.4",
-        "psr/cache": "^1.0 || ^2.0 || ^3.0",
-        "psr/simple-cache": "^1.0 || ^2.0 || ^3.0",
+        "psr/cache": "^2.0 || ^3.0",
+        "psr/simple-cache": "^2.0 || ^3.0",
         "paragonie/random_compat": ">= 2",
-        "sebastian/comparator": "^1.2.3 || ^4.0",
-        "yoast/phpunit-polyfills": "^1.0",
+        "sebastian/comparator": "^1.2.3 || ^4.0 || ^5.0",
+        "yoast/phpunit-polyfills": "^2.0",
         "dms/phpunit-arraysubset-asserts": "^0.4.0"
     },
     "suggest": {
diff --git a/phpstan.neon b/phpstan.neon
index 555c8e953e..0597cedc8b 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -5,17 +5,18 @@ parameters:
   parallel:
     processTimeout: 300.0
 
-  excludes_analyse:
-    # Guzzle V5 classes & interfaces changed in V6
-    - %rootDir%/../../../src/Handler/GuzzleV5/*
-    - %rootDir%/../../../src/Crypto/Polyfill/*
-    - src/data/*
+  excludePaths:
+      # Guzzle V5 classes & interfaces changed in V6
+      - %rootDir%/../../../src/Handler/GuzzleV5/*
+      - %rootDir%/../../../src/Crypto/Polyfill/*
+      - src/data/*
 
   ignoreErrors:
     # Intentional
     - '#Aws\\Api\\Parser\\Crc32ValidatingParser::__construct\(\) does not call parent constructor from Aws\\Api\\Parser\\AbstractParser\.#'
     - '#Aws\\S3\\(RetryableMalformedResponse|GetBucketLocation|AmbiguousSuccess)Parser::__construct\(\) does not call parent constructor from Aws\\Api\\Parser\\AbstractParser\.#'
     - '#Unsafe usage of new static\(\)\.#'
+    - '#should return .* but return statement is missing#'
 
     # HashContext definition sometimes not found by static analysis
     - '#Property Aws\\PhpHash::\$context has unknown class HashContext as its type\.#'
diff --git a/src/functions.php b/src/functions.php
index 5f4d98ad5a..c8f5077486 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -300,11 +300,6 @@ function default_user_agent()
         return \GuzzleHttp\default_user_agent();
     }
 
-    // If Guzzle 5 installed
-    if ($version === 5) {
-        return \GuzzleHttp\Client::getDefaultUserAgent();
-    }
-
     throw new \RuntimeException('Unknown Guzzle version: ' . $version);
 }