Change product's price

Hello,

I have OC v4.0.2.3 with default theme. I changed product's price for effective immediately from today for example, but the price also changed all the transactions in the past invoices record. It makes customers confusion and very upset. It should keeps all the transactions in the past unchanged as it. Please advise How to fix the issue? Thanks in advance!

OpenCart doesn't do that. It gets the prices from the oc_order_product table, which isn't changed when you edit a product.

Could be caused by one of your extensions.

As you should know by now, don't use 4.0.2.3 for a live website. OpenCart 4 is still subject to development and bugfixes, and should only be used by developers. Use 3.0.4.0, or at least wait until the upcoming 4.1.0.4.