System Variable 447: Show Warning Message “Are You Sure” When Clicking on the Finalize Invoice Button That Inserts the Invoice Number

Use this System Variable to determine if a warning message should be displayed if a Sales Invoice is finalized.

This System Variable is disabled by default. When it is enabled and you click Finalize Invoice on the Header tab in Jobs > Invoice, you will be prompted with the following error message:
This will finalize the invoice. Further editing will not be possible. Continue?