diff --git a/src/Transport/Curl.php b/src/Transport/Curl.php
index 891d2e7e8..a76f24a53 100644
--- a/src/Transport/Curl.php
+++ b/src/Transport/Curl.php
@@ -27,7 +27,6 @@
 final class Curl implements Transport {
 	const CURL_7_10_5 = 0x070A05;
 	const CURL_7_16_2 = 0x071002;
-	const CURL_7_22_0 = 0x071600;
 
 	/**
 	 * Raw HTTP data
@@ -383,7 +382,7 @@ private function setup_handle($url, $headers, $data, $options) {
 		$options['hooks']->dispatch('curl.before_request', [&$this->handle]);
 
 		// Force closing the connection for old versions of cURL (<7.22).
-		if ($this->version < self::CURL_7_22_0 && !isset($headers['Connection'])) {
+		if (!isset($headers['Connection'])) {
 			$headers['Connection'] = 'close';
 		}