Pfcg roles after ecc to S/4 Hana conversion

Hello All,

Currently I am working in to a ecc to S/4 Hana conversion project. I do have few queries from Security perspective. Appreciate your prompt response on the same

1. What will be the impact on the ecc roles after conversion? How to check the impact? Will SU25 provide me all impact changes? Is it mandatory to run SU25 after conversion?

2. I believe I would need to build additional add on roles for Fiori app access and keep my ecc roles as it is. Kindly let me know if my understanding is correct.

Regards,

Vijay