diff --git a/.github/actions/build-docs/action.yml b/.github/actions/build-docs/action.yml
index 0ea4c920..e413cf5f 100644
--- a/.github/actions/build-docs/action.yml
+++ b/.github/actions/build-docs/action.yml
@@ -17,4 +17,4 @@ runs:
           --ignore-tags psalm-return \
           --visibility public \
           --defaultpackagename "LaunchDarkly" \
-          --title "LaunchDarkly PHP SDK 6.5.0" # x-release-please-version
+          --title "LaunchDarkly PHP SDK 6.5.1" # x-release-please-version
diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index b85605b8..e1cfad1c 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "6.5.0"
+  ".": "6.5.1"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7765cd04..854267ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 All notable changes to the LaunchDarkly PHP SDK will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org).
 
+## [6.5.1](https://github.com/launchdarkly/php-server-sdk/compare/6.5.0...6.5.1) (2025-03-17)
+
+
+### Bug Fixes
+
+* php 8.4 deprecation for implicitly nullable parameters ([#219](https://github.com/launchdarkly/php-server-sdk/issues/219)) ([1143a16](https://github.com/launchdarkly/php-server-sdk/commit/1143a16bbc537c7cc076e8e7022be1cb81b4087c))
+
 ## [6.5.0](https://github.com/launchdarkly/php-server-sdk/compare/6.4.0...6.5.0) (2025-03-13)
 
 
diff --git a/src/LaunchDarkly/LDClient.php b/src/LaunchDarkly/LDClient.php
index 9bed69a5..e8271b99 100644
--- a/src/LaunchDarkly/LDClient.php
+++ b/src/LaunchDarkly/LDClient.php
@@ -39,7 +39,7 @@ class LDClient
      * The current SDK version.
      * @var string
      */
-    const VERSION = '6.5.0'; // x-release-please-version
+    const VERSION = '6.5.1'; // x-release-please-version
 
     protected string $_sdkKey;
     protected string $_baseUri;