Use standard boolean operator

src/Network/HTTPClient/Response/CurlResult.php

@@ -230,7 +230,7 @@ class CurlResult implements ICanHandleHttpResponses
 
 			$this->redirectUrl = (string)Uri::fromParts((array)$redirect_parts);
 			$this->isRedirectUrl = true;
-			$this->redirectIsPermanent = $this->returnCode == 301 or $this->returnCode == 308;
+			$this->redirectIsPermanent = $this->returnCode == 301 || $this->returnCode == 308;
 		} else {
 			$this->isRedirectUrl = false;
 			$this->redirectIsPermanent = false;