If your application is running behind an nginx / apache you can impose a 301 or 302 redirect at that reverse proxy ( I would suggest 302 since 301 redirects can be cached by the browsers. But if you are for sure you will not need to change it in future again, you can use 301 redirect.)
you can add the following to your existing Nginx config
location /SSO/ {
return 302 /oauth/v2/login?$query_string;
}