Update or remake (CMS to YII)?

Question

CMS

Good afternoon, colleagues
, there is a website (CMS) on yii, it needs to be updated or redone on new technologies, the system was developed in the distant ~ 2010 documentation, there is nothing)
the question is, is it better to understand how everything is arranged there and update or write something similar from scratch?
Thanks in advance for your comments

Answer 1

It is better to evaluate the labor costs for the existing and new required functionality, and only then make a decision.