This release also went out as patch 8.4.18.1 on September 1, 2026. The patch carries the four 8.4.18 fixes plus one additional agenda fix, listed separately below.

Stripe payment error on registrations with specific decimal balances

Registrants could see “an error occurred attempting to prepare to process your payment” when they reached the Stripe payment section. Specific combinations of decimal charges and partial payments caused a floating-point miscalculation that sent Stripe an invalid repeating-decimal amount, which Stripe rejected. Amounts are now rounded correctly before they're sent.

Registration › Payments › Stripe SCM-56143

Speaker and Reviewer Portal settings not fully copied with the event

Copying an event with Speaker and Reviewer Portals selected did not carry all portal configuration into the new event. Portal pages, layout, branding, and settings, including the Read Only toggle, are now fully copied.

Events › Copy Event › Speaker Portal SCM-56152

Speaker and Reviewer Portal login page not visible after an event copy

Copying an event with a Speaker or Reviewer Portal configured left the portal unusable: the login page would not display, and saving portal pages produced a JavaScript error. Portals in copied events now inherit their page content and configuration from the original event.

Events › Copy Event › Speaker Portal SCM-56198

Custom session fields missing from speaker confirmation emails in copied events

Custom session field values submitted through the Speaker Portal's Submit Proposal form appeared blank in the Abstract Submit confirmation email after an event was copied. Email templates in copied events now reference the new event's custom session field records instead of the source event's.

Events › Copy Event › Speaker Portal › Emails SCM-56150

Canceling an agenda item past a validation error left guest assignments in place

Canceling an agenda item after a validation error caused an application error and left guest registrants assigned to the item, so inventory counts fell out of sync. A one-character typo in a SQL statement, introduced during a security cleanup, made the guest-cancellation query invalid: only the primary registrant's item was canceled while assigned guests remained. The query has been corrected so cancellations cascade to all assigned guests.

Registration › Agenda SCM-56194