How to change h1 to h2 in related products?

From the point of view of the search engines there is no good that on the same page there are to h1 headings.

Could you give me an advice how to change the h1 to h2 ONLY for related products?

You can do that by editing the file "listing" of the view "product" via the menu Display->Views. You'll see the tags there. Note that this file is used for all the products listings.

We'll change that for modules in that file for next release.

I have changed this. For my purposes it's enough.

But for others maybe the problem if they use others modules.

Related products is a special case so I need they must have special template to override.

I think that is for future releases.