Roslyn,
Did you get any answer to this question? I would like to know the answer, too.

Yes, below is the response I received from Support.
There are two new GUID fields that were added in HRMS 2016 Q2 – TRANSGUID to UPEMBK and MASTGUID to UPEMPL. These are used for direct deposit.
GUID fields are created when a New Employee is Entered or Imported, which use the Payroll Application Views. It’s a Random 36 Character String value. UP does not update GUID fields if left blank. Making changes to UP data should only be done via the Payroll Application Views to ensure Data Integrity is maintained and there are no problems when upgrading to new versions of Payroll.

Thanks, that's perfect.

Well, I thought I had something to run with there.... but maybe not. Is there any documentation for using the Payroll Application Views?