You can now forward one-off, non-recurring receipts/invoices to DoubleAgent, which will hold them for you in one place. Then when it's convenient you can whizz through them all, sending each one to the right spot in FreeAgent.
It turns out this is quicker than starting in FreeAgent with an explanation or expense, and then trying to find the corresponding receipt/invoice among all your emails; and then clicking on the next explanation/expense and wading through your emails again, and again.
DoubleAgent has evolved two different ways of handling receipts: first came the receipt emails feature, which was designed to handle recurring receipts/invoices, e.g. your monthly web hosting invoice. You take the email from your supplier and forward it to DoubleAgent, where rules that you have set up attach the invoice to the appropriate bank transaction explanation.
Second came the receipt photos feature, which was designed for receipts you take photos of, allowing you to send them into FreeAgent quickly. These are almost always one-off purchases.
These two features work well but there's a gap: what do you do when you buy something online and the receipt/invoice is emailed to you? It's a one-off purchase, so you probably wouldn't have a Receipt Emails rule for it. And it's attached to an email (or is the email), so uploading it via Receipt Photos would be a bit awkward. It makes most sense to just forward the email to DoubleAgent, where you can upload it immediately just like a receipt photo. Which is exactly what you can now do.
The different ways DoubleAgent handles receipts came about for good reasons. I feel the next step is to unify them into one, intuitive way of handling all receipts, whether photographed or emailed, one-off or recurring. No promises on a release date though ;)