diff --git a/README.md b/README.md
index 4c13e69dd60..3ada79f374b 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ An easier path to great Page Experience for everyone. Powered by AMP.
 **Tags:** [page experience](https://wordpress.org/plugins/tags/page-experience), [performance](https://wordpress.org/plugins/tags/performance), [amp](https://wordpress.org/plugins/tags/amp), [mobile](https://wordpress.org/plugins/tags/mobile), [optimization](https://wordpress.org/plugins/tags/optimization), [accelerated mobile pages](https://wordpress.org/plugins/tags/accelerated-mobile-pages)  
 **Requires at least:** 5.3  
 **Tested up to:** 6.4  
-**Stable tag:** 2.5.0  
+**Stable tag:** 2.5.1  
 **License:** [GPLv2 or later](http://www.gnu.org/licenses/gpl-2.0.html)  
 **Requires PHP:** 7.4
 
@@ -113,6 +113,8 @@ Please see the [FAQs on amp-wp.org](https://amp-wp.org/documentation/frequently-
 
 ## Changelog
 
+**Version 2.5.1 is a maintenance and security release which fixes a reflected XSS vulnerability when mobile redirection is enabled.** For prior affected versions, the fix is backported to new patch releases: v2.0.12, v2.1.5, v2.2.5, v2.3.1, and v2.4.3. These are available in the WordPress.org Plugin Directory but not on GitHub.
+
 For the plugin’s changelog, please see [the Releases page on GitHub](https://github.com/ampproject/amp-wp/releases).
 
 ## Upgrade Notice
diff --git a/amp.php b/amp.php
index 9d3d7ca8536..bded6b3f00e 100644
--- a/amp.php
+++ b/amp.php
@@ -5,7 +5,7 @@
  * Plugin URI: https://amp-wp.org
  * Author: AMP Project Contributors
  * Author URI: https://github.com/ampproject/amp-wp/graphs/contributors
- * Version: 2.5.1-alpha
+ * Version: 2.5.1
  * License: GPLv2 or later
  * Requires at least: 5.3
  * Requires PHP: 7.4
@@ -15,7 +15,7 @@
 
 define( 'AMP__FILE__', __FILE__ );
 define( 'AMP__DIR__', dirname( __FILE__ ) );
-define( 'AMP__VERSION', '2.5.1-alpha' );
+define( 'AMP__VERSION', '2.5.1' );
 
 /**
  * Errors encountered while loading the plugin.