“How do I get a newer version of the product linked to and showing up on the old versions product page?”

Example from a book

Over the years many a seller has asked how to accomplish this and the answer has always been that only Amazon could set it up.

Well finally Amazon has provided something for sellers that is helpful on this - Adding or removing newer model link on detail page (direct link)

Newer version widget

When sellers release a newer model or versions of a product, Amazon will add a link or widget to the product detail page that can redirect the customer to the product detail page of the newer model. This is especially useful for customers when the older version is out of stock or has been discontinued.

In order to classify for a newer model, the product will require the same function, quantity, type, and style.

Note: These newer model relationships are not the same as the variation relationship. The variation products are fundamentally identical except for size or color.

In order to submit for a newer version relationship, see the Adding or removing new model link on detail page.

I’ve not tested this out so comments on that are especially welcomed!