diff --git a/.changes/nextrelease/update-error-level.json b/.changes/nextrelease/update-error-level.json
new file mode 100644
index 0000000000..33c6821c3e
--- /dev/null
+++ b/.changes/nextrelease/update-error-level.json
@@ -0,0 +1,7 @@
+[
+  {
+    "type": "enhancement",
+    "category": "",
+    "description": "Updates PHP runtime deprecation notice to `E_USER_DEPRECATION`"
+  }
+]
diff --git a/src/ClientResolver.php b/src/ClientResolver.php
index 781c3fb0bb..02f5270f14 100644
--- a/src/ClientResolver.php
+++ b/src/ClientResolver.php
@@ -1453,7 +1453,7 @@ private static function emitDeprecationWarning()
             .  " or set the environment variable AWS_SUPPRESS_PHP_DEPRECATION_WARNING"
             .  " to true.\nMore information can be found at: "
             .   "https://aws.amazon.com/blogs/developer/announcing-the-end-of-support-for-php-runtimes-8-0-x-and-below-in-the-aws-sdk-for-php/\n",
-            E_USER_WARNING
+            E_USER_DEPRECATED
         );
     }
 }
diff --git a/tests/ClientResolverTest.php b/tests/ClientResolverTest.php
index aa15a48884..638fabfc4f 100644
--- a/tests/ClientResolverTest.php
+++ b/tests/ClientResolverTest.php
@@ -1685,8 +1685,8 @@ public function testEmitsDeprecationWarning()
         }
 
         putenv('AWS_SUPPRESS_PHP_DEPRECATION_WARNING=false');
-        $this->expectWarning();
-        $this->expectWarningMessage('This installation of the SDK is using PHP version');
+        $this->expectDeprecation();
+        $this->expectDeprecationMessage('This installation of the SDK is using PHP version');
 
         $r = new ClientResolver(ClientResolver::getDefaultArguments());