PingToPay

"I've already paid" link (suggested by Femidko) — every reminder email now has a one-click link the client can use themselves. It pauses that invoice's reminders immediately and pings you to confirm — doesn't mark anything paid on its own, just stops the noise while you check. If you don't confirm either way within 5 business days, reminders quietly pick back up (covers the "I'll pay soon" that was read as "I already paid").

Duplicate detection (suggested by feech) — re-importing a CSV, or adding an invoice that matches one you already have (same client, amount, due date) now gets flagged before it's saved. You see the actual row it matches and choose to skip it or add it anyway, instead of it silently creating a second record and double-emailing your client.

Pause reminders, manually (suggested by RaslakHub) — for when a client replies disputing a line item instead of just being late. Reminders already forward straight to your real inbox when a client hits Reply, so you'll see that conversation — now you can also pause that one invoice's sequence with a click while you sort it out, and resume it yourself when it's settled. No auto-timer fighting you mid-conversation.

Paid invoices lock their numbers — once you mark something paid, the amount/currency/due date can't be edited anymore (name/email/description still can, for typo fixes). Closed invoices shouldn't be able to quietly change after the fact.

None of these were on my roadmap before this thread — all four came directly out of comments here. Thanks for taking the time to actually dig into the product instead of just skimming it.