Non-static method ZCRMConfigUtil::setConfigValues()

When I call ZCRMRestClient::initialize($config) using the PHP SDK I get:

Non-static method ZCRMConfigUtil::setConfigValues() should not be called statically in vendor/zohocrm/php-sdk/src/com/zoho/crm/library/common/ZCRMConfigUtil.php

My code is:

$config = [

  
  'client_id'
   => 
  $clientId
  ,
 
  'client_secret'
   => 
  $clientSecret
  ,
 
  'redirect_uri'
   => 
  $redirectUri
  ,
 
  'currentUserEmail'
   => 
  $currentUserEmail
  ,
 
  'accounts_url'
   => 
  'https://account.zoho.com'
  ,
 
  'token_persistence_path'
   => 
  'zcrm_oauthtokens.txt'
  ,
 
  'applicationLogFilePath'
   => 
  'ZCRMClientLibrary.log'
 
  ];
  
  ZCRMRestClient
  ::
  initialize
  (
  $config
  );