diff --git a/wp-includes/pluggable.php b/wp-includes/pluggable.php
index c53a723fc4..b5e39d7a19 100644
--- a/wp-includes/pluggable.php
+++ b/wp-includes/pluggable.php
@@ -158,6 +158,8 @@ if ( ! function_exists( 'wp_mail' ) ) :
 	 * be set using the {@see 'wp_mail_charset'} filter.
 	 *
 	 * @since 1.2.1
+	 * @since 5.5.0 is_email() is used for email validation,
+	 *              instead of PHPMailer's default validator.
 	 *
 	 * @global PHPMailer\PHPMailer\PHPMailer $phpmailer
 	 *
diff --git a/wp-includes/version.php b/wp-includes/version.php
index f588288138..021c1c5fa8 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50780';
+$wp_version = '5.8-alpha-50781';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.