Need recommendation for CakePHP Upgrade Path

We have a legacy application developed using Cake 1.3. It exposes an API that is currently used by multiple mobile-applications. We are unable to update the mobile applications.

A typical API request is ourapp/controller/method?parameters

We are rolling out a phased-wise update to the app using CakePHP 3, and are starting with an update to ONE specific controller/method set. (e.g. ourapp/controller1/method1?parameters)

What is a recommended approach to have only http://ourapp/controller1/method1?parameters served by the Cake3 app, with all other requests served by the existing Cake1.3 app?

Is there any way to implement this using CakePhp routes ?
Or is an Apache redirect / proxy approach more appropriate ?