2. Did fixed set of serial number work across different product updates? Or, I have to generate it again and give it to the customer when there's a new product update?
Thank you

In order to achieve this, please have a look over our "How do I make the properties in the package keep their values during Maintenance or Upgrade?" article.1. Hi, is there is a possible ways to save typed serial number and displayed it again so user didn't have to type it again when they launch the installer?
Yes, the serial number should work for a product upgrade.2. Did fixed set of serial number work across different product updates? Or, I have to generate it again and give it to the customer when there's a new product update?
I am not quite sure I understand your scenario here.Hi, it doesn't work, it keep displaying the value that I entered in Edit Property Dialog. It doesn't save the serial code that I entered to install the product.