diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7d790fe..8d9cfff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,13 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased](https://github.com/HubSpot/hubspot-php/compare/v5.1.0...HEAD)
+## [Unreleased](https://github.com/HubSpot/hubspot-php/compare/v5.1.1...HEAD)
+
+## [5.1.1]
+
+### Changed
+
+- Fix `Utils\OAuth2::getAuthUrl()` (don't add empty scopes or optional scopes to OAuth url).
 
 ## [5.1.0]
 
diff --git a/composer.json b/composer.json
index 0f007e0..8375652 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
     "name": "hubspot/hubspot-php",
-    "version": "5.1.0",
+    "version": "5.1.1",
     "description": "HubSpot PHP API client",
     "keywords": [ "hubspot", "api" ],
     "license": "Apache-2.0",