diff --git a/package.json b/package.json
index 83fe0ba0042..f6134180768 100644
--- a/package.json
+++ b/package.json
@@ -75,7 +75,7 @@
     "webpack-bundle-analyzer": "^4.9.1"
   },
   "yoast": {
-    "pluginVersion": "23.1-RC3"
+    "pluginVersion": "23.1-RC4"
   },
   "version": "0.0.0"
 }
diff --git a/readme.txt b/readme.txt
index 711d8c60252..b7f8272af15 100644
--- a/readme.txt
+++ b/readme.txt
@@ -4,7 +4,7 @@ Donate link: https://yoa.st/1up
 License: GPLv3
 License URI: http://www.gnu.org/licenses/gpl.html
 Tags: SEO, XML sitemap, Content analysis, Readability, Schema
-Tested up to: 6.5
+Tested up to: 6.6
 Stable tag: 23.0
 Requires PHP: 7.2.5
 
@@ -321,8 +321,12 @@ Release date: 2024-07-16
 
 #### Enhancements
 
-* Disabled an unneeded cleanup cronjob when indexables are disabled.
-* Removes unnecessary query when indexables are disabled.
+* Disables an unneeded cleanup cron job when indexables are disabled.
+* Removes an unnecessary query when indexables are disabled.
+
+#### Other
+
+* Sets the \"WordPress tested up to\" version to 6.6.
 
 = 23.0 =
 
diff --git a/tests/Unit/bootstrap.php b/tests/Unit/bootstrap.php
index 1a4a6b27cdc..15d92022104 100644
--- a/tests/Unit/bootstrap.php
+++ b/tests/Unit/bootstrap.php
@@ -40,7 +40,7 @@
 \define( 'YOAST_VENDOR_PREFIX_DIRECTORY', 'vendor_prefixed' );
 
 \define( 'YOAST_SEO_PHP_REQUIRED', '7.2.5' );
-\define( 'YOAST_SEO_WP_TESTED', '6.5.5' );
+\define( 'YOAST_SEO_WP_TESTED', '6.6' );
 \define( 'YOAST_SEO_WP_REQUIRED', '6.4' );
 
 if ( ! \defined( 'WPSEO_NAMESPACES' ) ) {
diff --git a/wp-seo-main.php b/wp-seo-main.php
index 456ed47a78e..f63778539a4 100644
--- a/wp-seo-main.php
+++ b/wp-seo-main.php
@@ -15,7 +15,7 @@
  * {@internal Nobody should be able to overrule the real version number as this can cause
  *            serious issues with the options, so no if ( ! defined() ).}}
  */
-define( 'WPSEO_VERSION', '23.1-RC3' );
+define( 'WPSEO_VERSION', '23.1-RC4' );
 
 
 if ( ! defined( 'WPSEO_PATH' ) ) {
@@ -35,7 +35,7 @@
 define( 'YOAST_VENDOR_PREFIX_DIRECTORY', 'vendor_prefixed' );
 
 define( 'YOAST_SEO_PHP_REQUIRED', '7.2.5' );
-define( 'YOAST_SEO_WP_TESTED', '6.5.5' );
+define( 'YOAST_SEO_WP_TESTED', '6.6' );
 define( 'YOAST_SEO_WP_REQUIRED', '6.4' );
 
 if ( ! defined( 'WPSEO_NAMESPACES' ) ) {
diff --git a/wp-seo.php b/wp-seo.php
index d6cd478a63d..061f981b0c5 100644
--- a/wp-seo.php
+++ b/wp-seo.php
@@ -8,7 +8,7 @@
  *
  * @wordpress-plugin
  * Plugin Name: Yoast SEO
- * Version:     23.1-RC3
+ * Version:     23.1-RC4
  * Plugin URI:  https://yoa.st/1uj
  * Description: The first true all-in-one SEO solution for WordPress, including on-page content analysis, XML sitemaps and much more.
  * Author:      Team Yoast