Online card and ACH payments on client invoices. Off by default for FSG — Wendee or Dean turns it on (PRD [T38]).
Today FSG clients pay by check or ACH against a QuickBooks invoice. Nothing changes until this is turned on.
When enabled, every client invoice email gets a Pay online button, payments post back to QuickBooks automatically and mark the invoice paid, and the project moves to Closed · paid. The card fee can be passed through as a surcharge where allowed (Wisconsin: yes, with disclosure).