When you click from any search engine link - view from the main page. Is it possible to?

Question

JavaScript

About 5 years ago, as a computer scientist, I was puzzled to create a website for our educational institution ... I created it and the site was successfully filled. In the spring, we decided that the design was outdated and we decided to move to a new engine ... Over the summer, I created a site with a slider and news. And the old one was moved to the Old subdomain.
September passed quietly, and in October they call me and ask why nothing has changed on the site? The boss comes in and sees the old site. And at first I did not even understand what was going on. I was just told that the site is still faded and not being updated. No information on new requirements.
***
The authorities enter through a search engine. And the old site is already overgrown with links.
I see 2 options.
1. Pop-up window that the site is old - “continue browsing” and “Switch to the new version of the site”
2. By default, a newcomer starts browsing from the main page
. The first is more correct from the user's point of view.
The second - from my superiors ...
We are an educational institution and the site is practically not used for work. Purely for posting new information...
In addition, according to the new standards of publicity, we are required to post information...
How will the search engines react to the first and second options?

Answer 1

Considering your situation, perhaps the option with a pop-up window stating that the site is old is just right. The only thing better is not a pop-up window (because many browsers / ad suppressors cut such things, and annoying). Just somewhere at the top in big red letters - you are viewing the old-archived version of the site. You can go to a new site in this URL.

Answer 2

301 redirects from the old version of the site to similar pages of the new one, search engines understand this point well.

Answer 3

1. Table of translation of old addresses into new ones and redirect with code 301
If no rules were found in the translation table, then
2. Redirect to internal search with code 302
by default, substitute a hypothetical version of the desired one in the search string ...
2.1. if it came from a search engine, then the search string can be taken from the headers (referrer) - see how Google Analytics picks it out
2.2. if the desired link is in CNC format ( /stranitca_o_chem_nibud ) - then the reverse transformation from transliteration
can also be broken up by a slash ( / ) and the resulting string can be eaten by google or Yandex through the API - they can give variants of the same string for alternative search attempts,
there are others options
If not found, then
3. From the search page, give the opportunity to go to the site map

Answer 4

Is it the responsibility of a computer science teacher to create websites? Are you being paid for this?
If not, you can read no further. If yes, then the claim of your management is justified, because. You were just too lazy to transfer the old content to the new engine. A redirect to a new site here would be more understandable than a strange notification for the user.

Answer 5

if it is not used, then what difference does it make how the search engines react, I would redirect from the old to the main page of the new one and that's it.

Answer 6

Logically, the new option should be displayed by default. And if someone knows about the old version of the site, then he will look for the "Old Version" button.
Those. if a person first came to the site, then he is redirected to a new version, and in the new version there should be a link to the old version. By clicking on the link in the session or in cookies, we save the flag to display the old version.
At least on all the major sites that I have seen, the new version is displayed by default, and in it a link to the old one.

Answer 7

Either I don’t understand something, or from the moment you transferred the “old” site to the Old subdomain, all links in the search engine cache are more “unusable” because they lead to the root domain ... Or the “new” site has the same URLs ( but then your managers should still go to the new site).
PS: What you want to do is usually done by the capabilities of the web server, there are several options - 302 redirect, URLrewrite, etc. have already been mentioned.

Answer 8

Add a referrer check to the code of the old site, if you came from Google - a redirect to the new site.