Is SAC reporting mandatory only on invoices or GSTR-1 as well for those with turnover less than 1.5?

This discussion seeks clarification on whether SAC (Services Accounting Code) reporting is mandatory on GSTR-1 for businesses with a turnover below ₹1.5 crore. While news reports suggest HSN/SAC must be on invoices for turnovers below ₹5 crore, the specific requirement for GSTR-1 remains unclear. The user has reviewed Notification 78/2020, which amends previous rules regarding HSN on tax invoices but doesn't explicitly mention GSTR-1.