diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4377558c..26eb9887 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Optimizely PHP SDK Changelog
 
+## 4.0.4
+October 15, 2026
+
+* Update: Allow `justinrainbow/json-schema` v6.x #298
+* Update: Allow `lastguest/murmurhash` v2.x; bucketing supports both the v1 and v2 APIs with identical results #298
+* Add bucketing tests for empty-string and UTF-8 bucketing IDs #298
+* Add CI job that tests against the latest supported dependency versions on PHP 8.1 and 8.2 #298
+
 ## 4.0.3
 May 20, 2026
 
diff --git a/src/Optimizely/Event/Builder/EventBuilder.php b/src/Optimizely/Event/Builder/EventBuilder.php
index f57b2139..87781636 100644
--- a/src/Optimizely/Event/Builder/EventBuilder.php
+++ b/src/Optimizely/Event/Builder/EventBuilder.php
@@ -39,7 +39,7 @@ class EventBuilder
     /**
      * @const string Version of the Optimizely PHP SDK.
      */
-    const SDK_VERSION = '4.0.3';
+    const SDK_VERSION = '4.0.4';
 
     /**
      * @var string URL to send event to.
diff --git a/tests/EventTests/EventBuilderTest.php b/tests/EventTests/EventBuilderTest.php
index 01f9234f..961ba95e 100644
--- a/tests/EventTests/EventBuilderTest.php
+++ b/tests/EventTests/EventBuilderTest.php
@@ -69,7 +69,7 @@ protected function setUp() : void
                 ]],
                 'revision' => '15',
                 'client_name' => 'php-sdk',
-                'client_version' => '4.0.3',
+                'client_version' => '4.0.4',
                 'anonymize_ip'=> false,
                 'enrich_decisions' => true,
             ];