Google, old site pages indexed. How i can remove old pages gracefully?

Question

I have create a new version of a site: new HTML structure, new styles, images, etc. The content of the site is the same (text are changed but the "concepts" are the same). This is the actual server root composition:

-www.examplesite.com/
   - index.php
   - styles/
   - html_pages/
   - old_site/
         - index.php
         - pag/

As we can see in this tree, the old_site is still on the server and is inside sub-folder (old_site). Technically there's no need to maintain the old site in the server, but this is a request from the customer. Troubles comes with products pages. In old and new site, there are some products pages, they are similar in the concept, the newer is simply an update of the same product page. So i have something like:

http://www.examplesite.com/html_pages/Prod-x-Abu.php
http://www.examplesite.com/old_site/pag/prodxabu.php

If I try to search something related to "Prod x Abu", Google shows me the old site version in first position. The new version is 2/3rds of the way down the result page.

How can I gracefully move the google result for Prod x Abu to the new site version? I said gracefully because I'm afraid to use solutions like:

• robots.txt deny for the sub folder old_site
• remove from indexing for the sub folder old_site with Google Search Console

I'm afraid because the traffic to the old_site sub folder is actually the only that bring users from Google research to the site. With a drastic approach I'll risk to make "invisible" the site on Google.

Maybe a 301 redirect in every page is a good solution?

Answer 1

Yes, a 301 redirect would be the way to go about it.

According to yoast,

Use a 301 redirect to permanently redirect a URL to a new destination. This way, you tell both visitors and search engine crawlers that this URL changed and a new destination is found. This the most common redirect.

Via - 6 questions about redirects for SEO | Yoast