diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5e0b9485..058f1584 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 3.3.1
+May 28th, 2020
+
+### Bug Fixes:
+- This release adds an SDK key param to Optimizely constructor. The user can now create an Optimizely instance only using an SDK key. Previously the user was required to create a HTTPProjectConfigManager, and pass it as a config manager in the constructor. ([#189](https://github.com/optimizely/php-sdk/pull/189), [#193](https://github.com/optimizely/php-sdk/pull/193)) 
+
 ## 3.3.0
 January 27th, 2020
 
diff --git a/src/Optimizely/Event/Builder/EventBuilder.php b/src/Optimizely/Event/Builder/EventBuilder.php
index 7300d26e..a765a6a7 100644
--- a/src/Optimizely/Event/Builder/EventBuilder.php
+++ b/src/Optimizely/Event/Builder/EventBuilder.php
@@ -38,7 +38,7 @@ class EventBuilder
     /**
      * @const string Version of the Optimizely PHP SDK.
      */
-    const SDK_VERSION = '3.3.0';
+    const SDK_VERSION = '3.3.1';
 
     /**
      * @var string URL to send event to.
diff --git a/tests/EventTests/EventBuilderTest.php b/tests/EventTests/EventBuilderTest.php
index 26100659..6a2a27a1 100644
--- a/tests/EventTests/EventBuilderTest.php
+++ b/tests/EventTests/EventBuilderTest.php
@@ -68,7 +68,7 @@ public function setUp()
                 ]],
                 'revision' => '15',
                 'client_name' => 'php-sdk',
-                'client_version' => '3.3.0',
+                'client_version' => '3.3.1',
                 'anonymize_ip'=> false,
                 'enrich_decisions' => true,
             ];