How to read file property (modified date, created date)

Mapper can definitely fix it, but if I’m trying to make the pipeline dynamic, and reusable, I will need some method can read the excel header row and upper case the whole header dynamically.

You can use an expression in the mapper like

$.mapKeys((value, key) => key.toUpperCase())

That should work for any header you want. Here’s more information on the mapKeys function.

EDIT: In the mapper you’ll want to set the Target Path for that expression to $. Here’s the configuration I used in my test.