Joining epay v2 (YII2)

You want to introduce online epay v2 payment into the current ticketing system.
At the moment, the old version of epay v1 is connected.
Leave compatibility with the old version. Switch epay api to take to the settings of the system.

Site - https://ticket.kinoteatr.kz
Documentation epay v1 - https://testpay.kkb.kz/doc/htm/
Documentation epay v2 - https://developer.homebank.kz/epay/platezhnaya-stranica

Stack: PHP7.x, YII2, MySql

Requirements for the result:
Yii2
Compliance with PSR standards.

The task is only for the developer, the studios are not considered.
No offer is considered without specifying the preliminary cost and timing of the offer.