We have a huge website written in a old (7 years old) modified version of CodeIgniter and we're stuck on php 5.4 because of that. This app started very very small but increased a huge deal in these years and we're doing changes to it on a daily basis, so the code is not quite clean, we have hacks everywhere, many versioned assets loaded at same time because they are dependencies of the layout, etc... anyway, not pretty at all.
We would like to move to Yii 2 because that's something we're very familiar with and we have other apps written in it, it supports higher versions of PHP, composer, etc etc, you get the point.
We don't have an army of devs so that some of us can rewrite the app from scratch and some of us continue developing the current one, thus i think we should start rewriting small parts of it and using nginx would redirect the traffic to the newly rewritten parts, and do so till the entire rewrite is done, basically for a while, both apps would run in parallel sharing same database but accessing various urls would access one app or the other.
Has any of you gone this road and can share the experience, some pointers, etc ?
