diff --git a/app/Controllers/Items.php b/app/Controllers/Items.php
index e864d76e3..4b9b0f4d6 100644
--- a/app/Controllers/Items.php
+++ b/app/Controllers/Items.php
@@ -635,10 +635,10 @@ class Items extends Secure_Controller
             $item_data['reorder_level'] = 0;
         }
 
-        $tax_category_id = intval($this->request->getPost('tax_category_id'));
+        $tax_category_id = $this->request->getPost('tax_category_id');
 
         if (!isset($tax_category_id)) {
-            $item_data['tax_category_id'] = '';
+            $item_data['tax_category_id'] = null;
         } else {
             $item_data['tax_category_id'] = empty($this->request->getPost('tax_category_id')) ? null : intval($this->request->getPost('tax_category_id'));
         }
diff --git a/app/Database/Migrations/20250716170000_MissingConfigKeys.php b/app/Database/Migrations/20250716170000_MissingConfigKeys.php
index 7c5673d3a..4ae39c9cc 100644
--- a/app/Database/Migrations/20250716170000_MissingConfigKeys.php
+++ b/app/Database/Migrations/20250716170000_MissingConfigKeys.php
@@ -4,7 +4,7 @@ namespace App\Database\Migrations;
 
 use CodeIgniter\Database\Migration;
 
-class MissingConfigKeys extends Migration
+class Migration_MissingConfigKeys extends Migration
 {
     /**
      * Perform a migration step.
diff --git a/app/Database/Migrations/20250729170000_NullableTaxCategoryId.php b/app/Database/Migrations/20250729170000_NullableTaxCategoryId.php
new file mode 100644
index 000000000..97daa4df2
--- /dev/null
+++ b/app/Database/Migrations/20250729170000_NullableTaxCategoryId.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Database\Migrations;
+
+use CodeIgniter\Database\Migration;
+
+class Migration_NullableTaxCategoryId extends Migration
+{
+    /**
+     * Perform a migration step.
+     */
+    public function up(): void
+    {
+        error_log('Migrating config table');
+
+        helper('migration');
+        execute_script(APPPATH . 'Database/Migrations/sqlscripts/3.4.2_missing_config_keys.sql');
+
+        error_log('Migrating config table');
+    }
+
+    /**
+     * Revert a migration step.
+     */
+    public function down(): void
+    {
+    }
+}
diff --git a/app/Database/Migrations/sqlscripts/3.4.2_nullable_tax_category_id.sql b/app/Database/Migrations/sqlscripts/3.4.2_nullable_tax_category_id.sql
new file mode 100644
index 000000000..cc811f2dd
--- /dev/null
+++ b/app/Database/Migrations/sqlscripts/3.4.2_nullable_tax_category_id.sql
@@ -0,0 +1,3 @@
+-- Migration to make tax_category_id nullable in ospos_items
+ALTER TABLE ospos_items
+    MODIFY COLUMN tax_category_id INT NULL;