Field help (SWISUP1) 

This field is related to the activity code KSW – Switzerland.
This is an extra field which can be activated in the Payment entry type definition. It can be used when PostFinance bank files (EZAG/OPAE format) are generated. It allows to enter additional paying instructions like Personally or Urgent.
Possible usage also depends on the payment transaction type to be generated in the bank file as not all PostFinance payment transaction types support additional instructions.