What is a more formal way of saying "more on that later"?

It depends upon the precise circumstances. Do you already have information for later inclusion, or are you awaiting new information ?

In the first case : "I will provide more data / details later on".

In the second case : "Further information will be provided as it becomes available".

M.O.T.L!!!

We'll be in touch.

For the time being this much of information will do,later on you can provide me the details on this matter.

In the future, we will discuss

I will talk to you later about...

"In the future, we will discuss. . ."

If you want the Latin: "vide infra"

We'll revisit that.

Let's cover this in more detail later on! (or at a later date)