3816003 - How do I use Financial Integration Service (FIS) v4 with Expense Pay and Invoice Pay?

I have Financial Integration Service (FIS) v4 enabled (or I am planning to enable it), and I need to understand how it interacts with my Expense Pay and Invoice Pay setup. I want to know what changes in the payment flow when FIS is active, whether batch closing is still required, and what happens if a posting confirmation fails before payments are sent to the bank.

I also want to understand how FIS relates to Invoice Pay, specifically whether FIS handles invoice payment confirmation or if a separate process is needed for that.

Using Financial Integration Service (FIS) v4 with Expense Pay and Invoice Pay — batch behavior, posting confirmation, and payment guidelines , KBA , CON-INT , Integrations , Problem