Recalculate an invoice recurrence date

When to use this endpoint

Use this after changing recurrence timing. InvoiceRecurring_save already invokes it automatically.

The request must authenticate with signed API-key fields or a logged-in CRM session and is scoped to the authenticated tenant.

The handler performs no additional invoice page, record-owner, or department permission check unless stated below.

Parameter	Type	Required	Description
`id`	Positive integer	Yes	Existing recurrence ID.

$result = FM_api('InvoiceRecurring_recalculateNDate', ['id' => '42']);

{
  "ok": 1
}

Response	Condition
`{"error":"not logged in"}`	No authenticated tenant context is available. Invalid signed credentials can be rejected by the dispatcher before the handler runs.
`{"error":"missing or invalid parameter: id"}`	ID is absent or zero.
`{"error":"recurrence does not exist"}`	No matching tenant row exists.
`{"error":"invalid on_arr"}`	An interval-based recurrence has a non-positive interval.

Legacy application errors may be returned with HTTP 200. Check the decoded response for error, not only the HTTP status.

every=0 selects the next configured weekday; 1 configured zero-based days of a month; 2 configured zero-based days of a year; 3–6 intervals of days, weeks, approximate 30-day months, or approximate 365.242-day years.
Interval schedules start from the latest generated invoice date. If none exists, legacy date coercion is used; callers should normally create recurrence links through InvoiceRecurring_save.
The selected time is just after midnight in the server timezone and must be later than the current server time.

Updates ndate and last_edited.
Recomputes the global employer account’s invoice_next_recurrence as the tenant’s earliest nonzero next-run time.

Not called directly by CRM1; recurrence saves invoke it server-side.

Not called directly by CRM2; recurrence saves invoke it server-side.