diff --git a/wp-includes/Requests/Transport/cURL.php b/wp-includes/Requests/Transport/cURL.php
index 5f5c5dfb0a..04914440e6 100644
--- a/wp-includes/Requests/Transport/cURL.php
+++ b/wp-includes/Requests/Transport/cURL.php
@@ -309,6 +309,11 @@ class Requests_Transport_cURL implements Requests_Transport {
 	protected function setup_handle($url, $headers, $data, $options) {
 		$options['hooks']->dispatch('curl.before_request', array(&$this->handle));
 
+		// Force closing the connection for old versions of cURL (<7.22).
+		if ( ! isset( $headers['Connection'] ) ) {
+			$headers['Connection'] = 'close';
+		}
+
 		$headers = Requests::flatten($headers);
 
 		if (!empty($data)) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 3fb973936d..c0195b2b58 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37429';
+$wp_version = '4.6-alpha-37430';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.