How does “How the ageing is worked out” work on the Aged Receivables page?

An invoice is aged by the days between its due date and the as-of date: Current is not yet due, then 1–30, 31–60, 61–90 and over 90 days. The as-of date lets you reproduce a month-end position after the event — invoices paid since are still outstanding as at that day. The figures come from the Xero sync's copy of the invoices, so the sync time under the title is the freshness of the whole report; Refresh re-reads that copy and does not call Xero. Where: Aged Receivables (/accounts/sales/aged-receivables).