When upgrading from 11 to 13 what about sso authentication?

hello,

When upgrading from version 11 to 13. The version 11 currently has SSO CookieAuth enabled, with external authentication system. Will it cause any problem after the upgrade? Or can I continue with the upgrade and will able to continue to log in after login. I have been trying to access localaccess page on my app server. But I have not been able to do that. Thanks for  any guidance.