Can I run two Kirby versions (2.x and 3.x) under the same domain?

We are running a huge Kirby 2.5.14 website (plus 500 pages) on an Apache 2.4.6 server with PHP Version 7.2.19. Our client is currently not willing to pay for the migration to Kirby 3.x. So out of curiosity we copied the Kirby 2.5.14 website to a new web server with Apache 2.4.38 with HTTP/2 enabled and PHP Version 8.0.17.

In theory the new web server will allow us to update to Kirby 3.x BUT since

a) the customer won’t pay the migration and
b) 95% of the website run fine on the new server

the idea is to only migrate those pages, that don’t ran flawless on the new system. And maybe migrate further pages on a step by step basis in the future.

Therefore my question is, is there a way to install both Kirby versions in parallel and let selectively run web pages on the new Kirby version and the rest on the old system under the same domain?

PS I know this setup / situation is kind of a nightmare, but you know … “clients”

THX Yves

Technically you can - but I doubt that it is worth the effort. If you really would like to serve content from one domain you need to setup a load balancer (kind of reverse proxy) which serve the clients from the 2 backend web server. A set of rules on the load balancer steers which front-end url will be served from which backend.

I just had another idea: maybe I can switch the PHP version only for certain web pages, that won’t run with PHP 8.0. Laravel Valet has a similar concept, where you could have different PHP versions. Maybe this is something I can configure in the Apache Config.

I don’t quite understand why you updated to PHP 8.0 instead of sticking with 7.4 for the moment? Why make things so complicated?

Of course you can run different PHP versions even within the same virtual host but in your initial post you wanted to run different Kirby versions and thats might make it almost impossible from within one virtual host.

The reason is speed. Our client is fixated on Core Web Vitals though he does everything on his part to sabotage us with massive image sliders, external widgets to integrate and lots of other slowing stuff. And we poor have to keep the site running in a snappy manner in the background.

Already with HTTP/2 and PHP 8.0 the Lighthouse index went approx. 20 points up so this is a nice gain and of course we told the client it would be even more if he’s willing to upgrade to Kirby 3 but he won’t pay for the to expected massive upgrade costs. Therefore we are looking for ways to run the site on some kind of hybrid system (either two Kirby versions or two PHP versions) to have the speed gains and maybe migrating slow & secretly under the hood from K2 to K3.

Therefore thanks for all the suggestions so far.