diff --git a/wp-includes/version.php b/wp-includes/version.php
index 37fdc83791..04cf13a367 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31390';
+$wp_version = '4.2-alpha-31391';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
diff --git a/wp-includes/wp-db.php b/wp-includes/wp-db.php
index c8f456ef63..539324091d 100644
--- a/wp-includes/wp-db.php
+++ b/wp-includes/wp-db.php
@@ -2801,7 +2801,14 @@ class wpdb {
 			case 'set_charset' :
 				return version_compare( $version, '5.0.7', '>=' );
 			case 'utf8mb4' :      // @since 4.1.0
-				return version_compare( $version, '5.5.3', '>=' );
+				if ( version_compare( $version, '5.5.3', '<' ) ) {
+					return false;
+				}
+				if ( $this->use_mysqli ) {
+					return mysqli_get_client_version( $this->dbh ) >= 50503;
+				} else {
+					return mysql_get_client_version( $this->dbh ) >= 50503;
+				}
 		}
 
 		return false;