diff --git a/wp-includes/l10n.php b/wp-includes/l10n.php
index 57e9a06b73..0687ca6b89 100644
--- a/wp-includes/l10n.php
+++ b/wp-includes/l10n.php
@@ -745,17 +745,22 @@ function get_available_languages( $dir = null ) {
  *
  * @since 3.7.0
  *
- * @param string $type What to search for. Accepts 'plugins', 'themes'.
+ * @param string $type What to search for. Accepts 'plugins', 'themes', 'core'.
  * @return array Array of language data.
  */
 function wp_get_installed_translations( $type ) {
-	if ( $type !== 'themes' && $type !== 'plugins' )
+	if ( $type !== 'themes' && $type !== 'plugins' && $type !== 'core' )
 		return array();
 
-	if ( ! is_dir( WP_LANG_DIR ) || ! is_dir( WP_LANG_DIR . "/$type" ) )
+	$dir = 'core' === $type ? '' : "/$type";
+
+	if ( ! is_dir( WP_LANG_DIR ) )
 		return array();
 
-	$files = scandir( WP_LANG_DIR . "/$type" );
+	if ( $dir && ! is_dir( WP_LANG_DIR . $dir ) )
+		return array();
+
+	$files = scandir( WP_LANG_DIR . $dir );
 	if ( ! $files )
 		return array();
 
@@ -766,11 +771,13 @@ function wp_get_installed_translations( $type ) {
 			continue;
 		if ( substr( $file, -3 ) !== '.po' )
 			continue;
-		if ( ! preg_match( '/(.*)-([A-Za-z_]{2,6}).po/', $file, $match ) )
+		if ( ! preg_match( '/(?:(.+)-)?([A-Za-z_]{2,6}).po/', $file, $match ) )
 			continue;
 
 		list( , $textdomain, $language ) = $match;
-		$language_data[ $textdomain ][ $language ] = wp_get_pomo_file_data( WP_LANG_DIR . "/$type/$file" );
+		if ( '' === $textdomain )
+			$textdomain = 'default';
+		$language_data[ $textdomain ][ $language ] = wp_get_pomo_file_data( WP_LANG_DIR . "$dir/$file" );
 	}
 	return $language_data;
 }
diff --git a/wp-includes/update.php b/wp-includes/update.php
index 1d2e1cba17..79903f5a03 100644
--- a/wp-includes/update.php
+++ b/wp-includes/update.php
@@ -28,6 +28,8 @@ function wp_version_check() {
 	$php_version = phpversion();
 
 	$current = get_site_transient( 'update_core' );
+	$translations = wp_get_installed_translations( 'core' );
+
 	if ( ! is_object($current) ) {
 		$current = new stdClass;
 		$current->updates = array();
@@ -85,10 +87,13 @@ function wp_version_check() {
 		'headers' => array(
 			'wp_install' => $wp_install,
 			'wp_blog' => home_url( '/' )
-		)
+		),
+		'body' => array(
+			'translations' => json_encode( $translations ),
+		),
 	);
 
-	$response = wp_remote_get($url, $options);
+	$response = wp_remote_post( $url, $options );
 
 	if ( is_wp_error( $response ) || 200 != wp_remote_retrieve_response_code( $response ) )
 		return false;
@@ -119,6 +124,10 @@ function wp_version_check() {
 	$updates->updates = $offers;
 	$updates->last_checked = time();
 	$updates->version_checked = $wp_version;
+
+	if ( isset( $body['translations'] ) )
+		$updates->translations = $body['translations'];
+
 	set_site_transient( 'update_core',  $updates);
 }