diff --git a/wp-includes/version.php b/wp-includes/version.php
index e8463c8c9f..82281d4a19 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-beta3-31946';
+$wp_version = '4.2-beta3-31947';
 
 /**
  * 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 91ad6f2286..ac9f24e6cd 100644
--- a/wp-includes/wp-db.php
+++ b/wp-includes/wp-db.php
@@ -2219,6 +2219,12 @@ class wpdb {
 		foreach ( $columns as $column ) {
 			if ( ! empty( $column->Collation ) ) {
 				list( $charset ) = explode( '_', $column->Collation );
+
+				// If the current connection can't support utf8mb4 characters, let's only send 3-byte utf8 characters.
+				if ( 'utf8mb4' === $charset && ! $this->has_cap( 'utf8mb4' ) ) {
+					$charset = 'utf8';
+				}
+
 				$charsets[ strtolower( $charset ) ] = true;
 			}