Version 5.0.0 release

system/Login/Handler/OAuth2/OAuth2.php

@@ -588,7 +588,7 @@ abstract class OAuth2 extends Handler
 
 			if( $this->pkceSupported === TRUE )
 			{
-				$post['code_verifier'] = Request::i()->cookie['codeVerifier'] ?: NULL;
+				$post['code_verifier'] = Request::i()->cookie['codeVerifier'] ?? NULL;
 			}
 
 			$data = $this->_authenticatedRequest( $this->tokenEndpoint(), $post );