diff --git a/debts.php b/debts.php
index 10e492b..12e1306 100644
--- a/debts.php
+++ b/debts.php
@@ -4,9 +4,10 @@ $user = require_auth();
 
 $activeNav = 'debts';
 $pageTitle = tr('الديون والفواتير الآجلة', 'Debts & Unpaid Bills');
-require_once 'includes/header.php';
-
 $pdo = db();
+$debtsLoadError = '';
+$unpaidSales = [];
+$debtsByCustomer = [];
 
 // Handle Mark as Paid
 if (isset($_GET['mark_paid'])) {
@@ -20,17 +21,67 @@ if (isset($_GET['mark_paid'])) {
     redirect_to('debts.php');
 }
 
-// Fetch all unpaid sales
-$sqlUnpaid = "SELECT s.*, c.name as c_name, c.phone as c_phone 
-              FROM sales_orders s 
-              LEFT JOIN customers c ON s.customer_id = c.id 
-              WHERE s.payment_status = 'unpaid' 
-              ORDER BY s.sale_date DESC";
-$stmtUnpaid = $pdo->query($sqlUnpaid);
-$unpaidSales = $stmtUnpaid->fetchAll(PDO::FETCH_ASSOC);
+try {
+    $salesColumns = [];
+    foreach ($pdo->query('SHOW COLUMNS FROM sales_orders')->fetchAll(PDO::FETCH_ASSOC) as $column) {
+        $salesColumns[$column['Field']] = true;
+    }
+
+    $hasCustomersTable = false;
+    $customerColumns = [];
+    $customersTable = $pdo->query("SHOW TABLES LIKE 'customers'");
+    if ($customersTable && $customersTable->fetchColumn()) {
+        $hasCustomersTable = true;
+        foreach ($pdo->query('SHOW COLUMNS FROM customers')->fetchAll(PDO::FETCH_ASSOC) as $column) {
+            $customerColumns[$column['Field']] = true;
+        }
+    }
+
+    $selectParts = [
+        's.id',
+        's.receipt_no',
+        's.sale_date',
+        's.total_amount',
+        isset($salesColumns['customer_id']) ? 's.customer_id' : 'NULL AS customer_id',
+        isset($salesColumns['customer_name']) ? 's.customer_name' : 'NULL AS customer_name',
+        'NULL AS c_name',
+        'NULL AS c_phone',
+    ];
+
+    $joinSql = '';
+    if ($hasCustomersTable && isset($salesColumns['customer_id']) && isset($customerColumns['id'])) {
+        $joinSql = ' LEFT JOIN customers c ON s.customer_id = c.id ';
+        if (isset($customerColumns['name'])) {
+            $selectParts[6] = 'c.name AS c_name';
+        }
+        if (isset($customerColumns['phone'])) {
+            $selectParts[7] = 'c.phone AS c_phone';
+        }
+    }
+
+    if (isset($salesColumns['payment_status'])) {
+        $whereSql = " WHERE s.payment_status = 'unpaid'";
+    } elseif (isset($salesColumns['payment_method'])) {
+        $whereSql = " WHERE s.payment_method = 'pay_later'";
+    } else {
+        $whereSql = ' WHERE 1 = 0';
+    }
+
+    $sqlUnpaid = 'SELECT ' . implode(', ', $selectParts)
+        . ' FROM sales_orders s'
+        . $joinSql
+        . $whereSql
+        . ' ORDER BY s.sale_date DESC';
+    $stmtUnpaid = $pdo->query($sqlUnpaid);
+    $unpaidSales = $stmtUnpaid ? $stmtUnpaid->fetchAll(PDO::FETCH_ASSOC) : [];
+} catch (Throwable $e) {
+    $debtsLoadError = tr(
+        'تعذر تحميل صفحة الديون بسبب اختلاف في هيكل قاعدة البيانات. احفظ التعديلات ثم أنشئ نسخة جديدة وأعد التحديث.',
+        'The debts page could not load because the deployed database schema is older than the current code. Save these changes, create a new version, then refresh the page.'
+    );
+}
 
 // Aggregate by customer
-$debtsByCustomer = [];
 foreach ($unpaidSales as $sale) {
     $cId = $sale['customer_id'] ?? 'unknown';
     if (!isset($debtsByCustomer[$cId])) {
@@ -47,12 +98,20 @@ foreach ($unpaidSales as $sale) {
 
 // Sort by highest debt
 uasort($debtsByCustomer, fn($a, $b) => $b['total'] <=> $a['total']);
+
+require_once 'includes/header.php';
 ?>
 
 <div class="d-flex justify-content-between align-items-center mb-4">
   <h1 class="h3 mb-0 text-gray-800"><?= h($pageTitle) ?></h1>
 </div>
 
+<?php if ($debtsLoadError !== ''): ?>
+    <div class="alert alert-warning" role="alert">
+        <?= h($debtsLoadError) ?>
+    </div>
+<?php endif; ?>
+
 <div class="row">
     <!-- Debts by Customer -->
     <div class="col-lg-4 mb-4">
diff --git a/includes/sale_form.php b/includes/sale_form.php
index 971af87..b31ac66 100644
--- a/includes/sale_form.php
+++ b/includes/sale_form.php
@@ -28,6 +28,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         $error = tr('اختر فرعاً صالحاً لهذه الصلاحية.', 'Choose a valid branch for this role.');
     } elseif (!in_array($paymentMethod, ['cash', 'card', 'transfer', 'pay_later'], true)) {
         $error = tr('اختر طريقة دفع صحيحة.', 'Choose a valid payment method.');
+    } elseif ($saleStatus === 'order' && !$customerId) {
+        $error = tr('يجب اختيار عميل للطلب المسبق.', 'You must select a customer for a pre-order.');
     } elseif ($paymentMethod === 'pay_later' && !$customerId) {
         $error = tr('يجب اختيار عميل مسجل للدفع الآجل.', 'You must select a registered customer for pay later.');
     } elseif (!is_array($items) || $items === []) {
@@ -732,10 +734,14 @@ function updateTotals(total, vat) {
 // Intercept form submission to check if items exist
 document.getElementById('smart-sale-form').addEventListener('submit', function(e) {
     const paymentMethod = document.querySelector('select[name="payment_method"]').value;
+    const saleStatus = document.querySelector('select[name="sale_status"]').value;
     const customerId = document.getElementById('formCustomerId').value;
     if (Object.keys(invoiceItems).length === 0) {
         e.preventDefault();
         Swal.fire({icon: 'warning', text: '<?= h(tr('الرجاء إضافة أصناف للفاتورة أولاً.', 'Please add items to the invoice first.')) ?>'});
+    } else if (saleStatus === 'order' && !customerId) {
+        e.preventDefault();
+        Swal.fire({icon: 'warning', text: '<?= h(tr('يجب اختيار عميل للطلب المسبق.', 'You must select a customer for a pre-order.')) ?>'});
     } else if (paymentMethod === 'pay_later' && !customerId) {
         e.preventDefault();
         Swal.fire({icon: 'warning', text: '<?= h(tr('يجب اختيار عميل مسجل للدفع الآجل.', 'You must select a registered customer for pay later.')) ?>'});
@@ -743,4 +749,4 @@ document.getElementById('smart-sale-form').addEventListener('submit', function(e
 });
 </script>
 
-<?php require __DIR__ . '/footer.php'; ?>
\ No newline at end of file
+<?php require __DIR__ . '/footer.php'; ?>