diff --git a/.changes/nextrelease/enhancement-php-version-bump.json b/.changes/nextrelease/enhancement-php-version-bump.json
new file mode 100644
index 0000000000..f287e37ad5
--- /dev/null
+++ b/.changes/nextrelease/enhancement-php-version-bump.json
@@ -0,0 +1,7 @@
+[
+  {
+    "type": "feature",
+    "category": "",
+    "description": "This version ends support for PHP versions below 7.2.5"
+  }
+]
\ No newline at end of file
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 0e64ca75ca..b2e279b069 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -16,7 +16,7 @@ jobs:
     strategy:
       #for each of the following versions of PHP, with and without --prefer-lowest
       matrix:
-        php-versions: ['5.5', '5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2']
+        php-versions: ['7.2.5', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2']
         composer-options: ['', '--prefer-lowest']
     #set the name for each job
     name: PHP ${{ matrix.php-versions }} ${{ matrix.composer-options }}
@@ -43,12 +43,6 @@ jobs:
     - name: Validate composer.json and composer.lock
       run: composer validate
 
-    #remove incompatible xdebug file if it exists
-    - if: ${{ matrix.php-versions == '5.5' }}
-      name: PHP 5.5
-      run: |
-        sudo rm -f /etc/php5/cli/conf.d/20-xdebug.ini
-
     #get dependencies
     - name: Install dependencies
       run: composer update ${{ matrix.composer-options }} --no-interaction --prefer-source
@@ -68,7 +62,7 @@ jobs:
       run: make test
 
     #static analysis
-    - if: ${{ matrix.php-versions >= '7.1' && matrix.php-versions < '8.0' && matrix.composer-options == '' }}
+    - if: ${{ matrix.php-versions < '8.0' && matrix.composer-options == '' }}
       name: Static analysis
       run: |
         composer require --dev nette/neon "^3.0"
@@ -79,11 +73,11 @@ jobs:
     - if:  ${{ matrix.composer-options == '' }}
       name: Package generation
       run: |
-        composer require guzzlehttp/psr7 "^1.9.1"
+        composer require guzzlehttp/psr7 "^1.9.1" -W
         composer update
         make package
 
     #generate code coverage
-    - if: ${{ (matrix.php-versions == '7.1' || matrix.php-versions == '8.0') && matrix.composer-options == '' }}
+    - if: ${{ (matrix.php-versions == '7.2.5' || matrix.php-versions == '8.0') && matrix.composer-options == '' }}
       name: Code coverage
       run: bash <(curl -s https://codecov.io/bash)
diff --git a/build/packager.php b/build/packager.php
index 836a055e01..1050a2e4c7 100644
--- a/build/packager.php
+++ b/build/packager.php
@@ -32,8 +32,6 @@
 $autoloaderContents = [
     'Aws/functions.php',
     'GuzzleHttp/functions_include.php',
-    'GuzzleHttp/Psr7/functions_include.php',
-    'GuzzleHttp/Promise/functions_include.php',
     'JmesPath/JmesPath.php',
 ];
 
diff --git a/build/test-phar.php b/build/test-phar.php
index f06ef6cfd6..48e66efced 100644
--- a/build/test-phar.php
+++ b/build/test-phar.php
@@ -20,8 +20,6 @@
 
 // React autoloader
 $checks = [
-    'GuzzleHttp\\Psr7\\stream_for',
-    'GuzzleHttp\\Promise\\inspect',
     'JmesPath\\search',
     'Aws\\dir_iterator',
 ];
@@ -33,4 +31,17 @@
     }
 }
 
+$classMethodChecks = [
+    'GuzzleHttp\\Promise\\Utils' => 'inspect',
+    'GuzzleHttp\\Psr7\\Utils' => 'streamFor',
+];
+
+foreach ($classMethodChecks as $class => $method) {
+    if (!method_exists($class, $method)
+    ) {
+        echo $class . '::' . $method . ' not found';
+        exit(1);
+    }
+}
+
 echo 'Version=' . Aws\Sdk::VERSION;
diff --git a/composer.json b/composer.json
index e96eaff9fc..cb770080d7 100644
--- a/composer.json
+++ b/composer.json
@@ -16,16 +16,16 @@
         "issues": "https://github.com/aws/aws-sdk-php/issues"
     },
     "require": {
-        "php": ">=5.5",
+        "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",
+        "guzzlehttp/promises": "^1.4.0 || ^2.0",
         "mtdowling/jmespath.php": "^2.6",
         "ext-pcre": "*",
         "ext-json": "*",
         "ext-simplexml": "*",
         "aws/aws-crt-php": "^1.0.4",
-        "psr/http-message": "^1.0"
+        "psr/http-message": "^1.0 || ^2.0"
     },
     "require-dev": {
         "composer/composer" : "^1.10.22",
@@ -33,7 +33,7 @@
         "ext-dom": "*",
         "ext-pcntl": "*",
         "ext-sockets": "*",
-        "phpunit/phpunit": "^4.8.35 || ^5.6.3 || ^9.5",
+        "phpunit/phpunit": "^5.6.3 || ^8.5 || ^9.5",
         "behat/behat": "~3.0",
         "doctrine/cache": "~1.4",
         "aws/aws-php-sns-message-validator": "~1.0",
diff --git a/src/AwsClient.php b/src/AwsClient.php
index c4b5271f8c..3b43b8260b 100644
--- a/src/AwsClient.php
+++ b/src/AwsClient.php
@@ -242,10 +242,6 @@ public function __construct(array $args)
         $this->addRecursionDetection();
         $this->addRequestBuilder();
 
-        if (!$config['suppress_php_deprecation_warning']) {
-            $this->emitDeprecationWarning();
-        }
-
         if (isset($args['with_resolved'])) {
             $args['with_resolved']($config);
         }
diff --git a/src/ClientResolver.php b/src/ClientResolver.php
index 34b2172379..ae74520b1d 100644
--- a/src/ClientResolver.php
+++ b/src/ClientResolver.php
@@ -280,13 +280,6 @@ class ClientResolver
             'doc'       => 'Set to false to disable checking for shared aws config files usually located in \'~/.aws/config\' and \'~/.aws/credentials\'.  This will be ignored if you set the \'profile\' setting.',
             'default'   => true,
         ],
-        'suppress_php_deprecation_warning' => [
-            'type'      => 'value',
-            'valid'     => ['bool'],
-            'doc'       => 'Set to false to disable the deprecation warning of PHP versions 7.2.4 and below',
-            'default'   => false,
-            'fn'        => [__CLASS__, '_apply_suppress_php_deprecation_warning']
-        ],
     ];
 
     /**
@@ -1026,21 +1019,6 @@ public static function _apply_idempotency_auto_fill(
         }
     }
 
-    public static function _apply_suppress_php_deprecation_warning($suppressWarning, array &$args) {
-        if ($suppressWarning) {
-            $args['suppress_php_deprecation_warning'] = true;
-        } elseif (!empty($_ENV["AWS_SUPPRESS_PHP_DEPRECATION_WARNING"])) {
-            $args['suppress_php_deprecation_warning'] =
-                $_ENV["AWS_SUPPRESS_PHP_DEPRECATION_WARNING"];
-        } elseif (!empty($_SERVER["AWS_SUPPRESS_PHP_DEPRECATION_WARNING"])) {
-            $args['suppress_php_deprecation_warning'] =
-                $_SERVER["AWS_SUPPRESS_PHP_DEPRECATION_WARNING"];
-        } elseif (!empty(getenv("AWS_SUPPRESS_PHP_DEPRECATION_WARNING"))) {
-            $args['suppress_php_deprecation_warning']
-                = getenv("AWS_SUPPRESS_PHP_DEPRECATION_WARNING");
-        }
-    }
-
     public static function _default_endpoint_provider(array $args)
     {
         $service =  isset($args['api']) ? $args['api'] : null;
diff --git a/src/CommandPool.php b/src/CommandPool.php
index 7cb1f94a12..d043422e21 100644
--- a/src/CommandPool.php
+++ b/src/CommandPool.php
@@ -75,7 +75,7 @@ public function __construct(
     /**
      * @return PromiseInterface
      */
-    public function promise()
+    public function promise(): PromiseInterface
     {
         return $this->each->promise();
     }
diff --git a/src/Crypto/AesDecryptingStream.php b/src/Crypto/AesDecryptingStream.php
index c1524cc18a..feafc469f2 100644
--- a/src/Crypto/AesDecryptingStream.php
+++ b/src/Crypto/AesDecryptingStream.php
@@ -65,7 +65,7 @@ public function getCurrentIv()
         return $this->cipherMethod->getCurrentIv();
     }
 
-    public function getSize()
+    public function getSize(): ?int
     {
         $plainTextSize = $this->stream->getSize();
 
@@ -80,12 +80,12 @@ public function getSize()
         return $plainTextSize;
     }
 
-    public function isWritable()
+    public function isWritable(): bool
     {
         return false;
     }
 
-    public function read($length)
+    public function read($length): string
     {
         if ($length > strlen($this->buffer)) {
             $this->buffer .= $this->decryptBlock(
@@ -101,7 +101,7 @@ public function read($length)
         return $data ? $data : '';
     }
 
-    public function seek($offset, $whence = SEEK_SET)
+    public function seek($offset, $whence = SEEK_SET): void
     {
         if ($offset === 0 && $whence === SEEK_SET) {
             $this->buffer = '';
diff --git a/src/Crypto/AesEncryptingStream.php b/src/Crypto/AesEncryptingStream.php
index 3b7c446754..2cb5ab696b 100644
--- a/src/Crypto/AesEncryptingStream.php
+++ b/src/Crypto/AesEncryptingStream.php
@@ -65,7 +65,7 @@ public function getCurrentIv()
         return $this->cipherMethod->getCurrentIv();
     }
 
-    public function getSize()
+    public function getSize(): ?int
     {
         $plainTextSize = $this->stream->getSize();
 
@@ -79,12 +79,12 @@ public function getSize()
         return $plainTextSize;
     }
 
-    public function isWritable()
+    public function isWritable(): bool
     {
         return false;
     }
 
-    public function read($length)
+    public function read($length): string
     {
         if ($length > strlen($this->buffer)) {
             $this->buffer .= $this->encryptBlock(
@@ -99,7 +99,7 @@ public function read($length)
         return $data ? $data : '';
     }
 
-    public function seek($offset, $whence = SEEK_SET)
+    public function seek($offset, $whence = SEEK_SET): void
     {
         if ($whence === SEEK_CUR) {
             $offset = $this->tell() + $offset;
diff --git a/src/Crypto/AesGcmDecryptingStream.php b/src/Crypto/AesGcmDecryptingStream.php
index 76feaa158b..6ca750008b 100644
--- a/src/Crypto/AesGcmDecryptingStream.php
+++ b/src/Crypto/AesGcmDecryptingStream.php
@@ -100,7 +100,7 @@ public function createStream()
         }
     }
 
-    public function isWritable()
+    public function isWritable(): bool
     {
         return false;
     }
diff --git a/src/Crypto/AesGcmEncryptingStream.php b/src/Crypto/AesGcmEncryptingStream.php
index 13357f52fb..0d706e421e 100644
--- a/src/Crypto/AesGcmEncryptingStream.php
+++ b/src/Crypto/AesGcmEncryptingStream.php
@@ -118,7 +118,7 @@ public function getTag()
         return $this->tag;
     }
 
-    public function isWritable()
+    public function isWritable(): bool
     {
         return false;
     }
diff --git a/src/HashingStream.php b/src/HashingStream.php
index 9b11e137bd..6622178e91 100644
--- a/src/HashingStream.php
+++ b/src/HashingStream.php
@@ -36,7 +36,7 @@ public function __construct(
         $this->callback = $onComplete;
     }
 
-    public function read($length)
+    public function read($length): string
     {
         $data = $this->stream->read($length);
         $this->hash->update($data);
@@ -50,14 +50,14 @@ public function read($length)
         return $data;
     }
 
-    public function seek($offset, $whence = SEEK_SET)
+    public function seek($offset, $whence = SEEK_SET): void
     {
-        if ($offset === 0) {
-            $this->hash->reset();
-            return $this->stream->seek($offset);
+        // Seeking arbitrarily is not supported.
+        if ($offset !== 0) {
+            return;
         }
 
-        // Seeking arbitrarily is not supported.
-        return false;
+        $this->hash->reset();
+        $this->stream->seek($offset);
     }
 }
diff --git a/src/Multipart/AbstractUploadManager.php b/src/Multipart/AbstractUploadManager.php
index 8e382c0e02..e663245e0d 100644
--- a/src/Multipart/AbstractUploadManager.php
+++ b/src/Multipart/AbstractUploadManager.php
@@ -88,7 +88,7 @@ public function upload()
      *
      * @return PromiseInterface
      */
-    public function promise()
+    public function promise(): PromiseInterface
     {
         if ($this->promise) {
             return $this->promise;
@@ -218,10 +218,8 @@ abstract protected function getCompleteParams();
     /**
      * Based on the config and service-specific workflow info, creates a
      * `Promise` for an `UploadState` object.
-     *
-     * @return PromiseInterface A `Promise` that resolves to an `UploadState`.
      */
-    private function determineState()
+    private function determineState(): UploadState
     {
         // If the state was provided via config, then just use it.
         if ($this->config['state'] instanceof UploadState) {
diff --git a/src/Rds/AuthTokenGenerator.php b/src/Rds/AuthTokenGenerator.php
index e58b7359d0..824d2b060e 100644
--- a/src/Rds/AuthTokenGenerator.php
+++ b/src/Rds/AuthTokenGenerator.php
@@ -47,8 +47,7 @@ public function createToken($endpoint, $region, $username, $lifetime = 15)
     {
         if (!is_numeric($lifetime) || $lifetime > 15 || $lifetime <= 0) {
             throw new \InvalidArgumentException(
-                "Lifetime must be a positive number less than or equal to 15, was {$lifetime}",
-                null
+                "Lifetime must be a positive number less than or equal to 15, was {$lifetime}"
             );
         }
 
diff --git a/src/S3/BatchDelete.php b/src/S3/BatchDelete.php
index 92439115cd..db81bebc5c 100644
--- a/src/S3/BatchDelete.php
+++ b/src/S3/BatchDelete.php
@@ -115,7 +115,7 @@ public static function fromIterator(
     /**
      * @return PromiseInterface
      */
-    public function promise()
+    public function promise(): PromiseInterface
     {
         if (!$this->cachedPromise) {
             $this->cachedPromise = $this->createPromise();
diff --git a/src/S3/ObjectCopier.php b/src/S3/ObjectCopier.php
index ca5922a92b..66e4446d90 100644
--- a/src/S3/ObjectCopier.php
+++ b/src/S3/ObjectCopier.php
@@ -7,6 +7,7 @@
 use Aws\Result;
 use Aws\S3\Exception\S3Exception;
 use GuzzleHttp\Promise\Coroutine;
+use GuzzleHttp\Promise\PromiseInterface;
 use GuzzleHttp\Promise\PromisorInterface;
 use InvalidArgumentException;
 
@@ -79,7 +80,7 @@ public function __construct(
      *
      * @return Coroutine
      */
-    public function promise()
+    public function promise(): PromiseInterface
     {
         return Coroutine::of(function () {
             $headObjectCommand = $this->client->getCommand(
diff --git a/src/S3/ObjectUploader.php b/src/S3/ObjectUploader.php
index 4bbc583a71..b73b7b1235 100644
--- a/src/S3/ObjectUploader.php
+++ b/src/S3/ObjectUploader.php
@@ -68,7 +68,7 @@ public function __construct(
     /**
      * @return PromiseInterface
      */
-    public function promise()
+    public function promise(): PromiseInterface
     {
         /** @var int $mup_threshold */
         $mup_threshold = $this->options['mup_threshold'];
diff --git a/src/S3/Transfer.php b/src/S3/Transfer.php
index 9228c807fc..600f441008 100644
--- a/src/S3/Transfer.php
+++ b/src/S3/Transfer.php
@@ -146,7 +146,7 @@ public function __construct(
      *
      * @return PromiseInterface
      */
-    public function promise()
+    public function promise(): PromiseInterface
     {
         // If the promise has been created, just return it.
         if (!$this->promise) {
diff --git a/src/Waiter.php b/src/Waiter.php
index ac1e001a84..74b2480131 100644
--- a/src/Waiter.php
+++ b/src/Waiter.php
@@ -3,6 +3,7 @@
 
 use Aws\Exception\AwsException;
 use GuzzleHttp\Promise\Coroutine;
+use GuzzleHttp\Promise\PromiseInterface;
 use GuzzleHttp\Promise\PromisorInterface;
 use GuzzleHttp\Promise\RejectedPromise;
 
@@ -89,7 +90,7 @@ public function __construct(
     /**
      * @return Coroutine
      */
-    public function promise()
+    public function promise(): PromiseInterface
     {
         return Coroutine::of(function () {
             $name = $this->config['operation'];
diff --git a/tests/Crypto/RandomByteStream.php b/tests/Crypto/RandomByteStream.php
index b14b7911e2..c0847b76d3 100644
--- a/tests/Crypto/RandomByteStream.php
+++ b/tests/Crypto/RandomByteStream.php
@@ -37,7 +37,7 @@ public function __construct($maxLength)
     /**
      * @return int|null
      */
-    public function getSize()
+    public function getSize(): ?int
     {
         return $this->maxLength;
     }