Info to Trade Customers before Launching a New Product

We've recently had a supplier of ours launch a new version of their product. They decided to not keep us informed of the new product.
Because the previous version had sold well we bought a lot of stock to get the lower price but this was just before the press release was sent out about the new version. Now the customers are keen to wait for the new version which leaves us with dead stock which we will have to discount to get rid of before the actual launch date of the new version otherwise we will not be able to sell them.

Discounting the old version isn't good for us as we earn less on each one and it isn't good for the manufacturer/ brand as everyone sees their products being sold much cheaper which leads to a lower perception of the brand (especially at a time when they are all over the news).

The lesson here is from a manufacture's point of view you should keep your main customers fully updated about new product launches even if it required them to have to sign a non disclosure agreement to keep it a secret.