Magento Invalid Method Mage Catalog Model Product IsDuplicable

Magento Invalid Method Mage Catalog Model Product IsDuplicable
Magento Invalid Method Mage Catalog Model Product IsDuplicable

New version theme is not working in old version.

After upgrading magento or when I design theme in magento 1.5.0.1 and use that theme in magento 1.4.2 that time my product page shows error like
Invalid method Mage_Catalog_Model_Product::isDuplicable

I find the solutin and its work for me.

Copy your product.php file from this path: app\code\core\Mage\Catalog\Model\product.php and replace in your maegnto folder.