The update is not yet downloadable via the update menu of HikaShop as we are waiting for feedbacks before rolling it out. If you want to update, you can download it directly on our website. It is available on the download page for the Starter edition and on your order details page for commercial editions
There is indeed no icon showing on the page as that's something different. RSS feeds can be subscribed via your browser menu. For example, on FireFox, you need to go in FireFox->Bookmarks->Subscribe to this page and you can see the feed created by HikaShop.
If you want an icon to link to that URL, you can use a module like that:
extensions.joomla.org/extensions/content...g/rss-syndicate/6878
Or just add the icon with the link to the feed page in your template or via a custom HTML module.