How to make different Bitrix cores on the same domain?

Question

1C-Bitrix

I must say right away that this is not about multi-site, the situation is as follows:
There is a rather old site, with the transition to a new template, there was a desire to clean it from garbage. Pages in the "new" design will appear gradually, I have a desire to generally put a clean Bitrix (possibly on a subdomain), and upload pages / sections to it as needed. But, I would like to keep the urls.
Of course, the versions will be in different folders on the server.
It turns out that at the url site.ru/page1/ the old core\database and so on, but at the url site.ru/page2/ there is another core\database\upload of the product.
where to drop? symlinks\virtual host settings or something, any thoughts do you have?
UDP: The site is on a server, without restrictions, you can do whatever you want.

Answer 1

Perhaps this way: we create two separated folders, each of them contains its own kernel.
In nginx, in the location settings, do we separate the urls, prescribing different ones
depending on the request?

Answer 2

Normally this won't work.
In order for this to somehow work, you need to comply with a number of conditions and restrictions:
1) You must be well versed in nginx in order to separate the root path depending on the domain address. You didn’t think which admin panel should open on /bitrix/ ? This is no longer a typical configuration, which you, by the way, also support.
2) You will forget about authorization, that is, a user of one site is not a user of another site, and when switching between pages you will lose authorization, just like some of the actions will be unavailable (for example, from site 1 you will not be able to edit article Y if it is not on site 1, and on site 2, respectively, site 1 will not see the articles of site 2 and vice versa). That is - all dynamic information (records of infoblocks, etc.) should be transferred immediately (and not 1-2 elements at a time)
3) In addition, system scripts will also work incorrectly. If there is no authorization on the site, and only guests, then there will be no problems at all, and if you want to update the online store in this way, it will take you more time and effort than writing a new one from 0 and developing a data migration script.
IMHO, your idea takes place but in a very rare case (less than 0.01%), and you will get much more inconveniences and restrictions.
Believe me, I know what I'm talking about - we served 2 Bitirx24 portals (boxed version), on one of which there was version 15 with CRM, and on the other 17 with the rest of the portal.