diff --git a/itflow-payment-idempotency-noschema.patch b/itflow-payment-idempotency-noschema.patch
deleted file mode 100644
index eb6c2d31..00000000
--- a/itflow-payment-idempotency-noschema.patch
+++ /dev/null
@@ -1,41 +0,0 @@
-diff --git a/cron/cron.php b/cron/cron.php
-index 04d879d..e1942c5 100644
---- a/cron/cron.php
-+++ b/cron/cron.php
-@@ -8,6 +8,14 @@ if (php_sapi_name() !== 'cli') {
-     die("This script must be run from the command line.\n");
- }
- 
-+// Only one run at a time. Autopay charges cards, so an overlapping run (the previous
-+// run still going when the next one fires) could bill the same invoice twice. The
-+// handle is held for the life of the process and released when it exits.
-+$cron_lock_handle = fopen(sys_get_temp_dir() . '/itflow_cron.lock', 'c');
-+if ($cron_lock_handle === false || !flock($cron_lock_handle, LOCK_EX | LOCK_NB)) {
-+    die("Cron is already running - exiting.\n");
-+}
-+
- require_once "../config.php";
- 
- // Set Timezone
-diff --git a/guest/guest_pay_invoice_stripe.php b/guest/guest_pay_invoice_stripe.php
-index d7c8c07..dcbe88a 100644
---- a/guest/guest_pay_invoice_stripe.php
-+++ b/guest/guest_pay_invoice_stripe.php
-@@ -223,8 +223,15 @@ if (isset($_GET['invoice_id'], $_GET['url_key']) && !isset($_GET['payment_intent
-         exit(WORDING_PAYMENT_FAILED);
-     }
- 
--    // Update Invoice Status
--    mysqli_query($mysqli, "UPDATE invoices SET invoice_status = 'Paid' WHERE invoice_id = $invoice_id");
-+    // Claim the invoice - the conditional UPDATE is the lock, and the row lock it takes
-+    // is what serialises concurrent requests carrying the same payment intent. A request
-+    // that loses the race matches 0 rows and must not book the payment a second time.
-+    mysqli_query($mysqli, "UPDATE invoices SET invoice_status = 'Paid' WHERE invoice_id = $invoice_id AND invoice_status NOT IN ('Draft', 'Paid', 'Cancelled')");
-+    if (mysqli_affected_rows($mysqli) !== 1) {
-+        error_log("Stripe payment - invoice $invoice_id was already settled by a concurrent request; skipping duplicate booking of $pi_id");
-+        header('Location: //' . $config_base_url . '/guest/guest_view_invoice.php?invoice_id=' . $invoice_id . '&url_key=' . $invoice_url_key);
-+        exit();
-+    }
- 
-     // Add Payment to History
-     mysqli_query($mysqli, "INSERT INTO payments SET payment_date = '$pi_date', payment_amount = $pi_amount_paid, payment_currency_code = '$pi_currency', payment_account_id = $stripe_account, payment_method = 'Stripe', payment_reference = 'Stripe - $pi_id', payment_invoice_id = $invoice_id");