How to Move Already Written CodeIgniter Code to Kohana?

Question

I've been using CodeIgniter for some time, and I liked it a lot. It looks like I need to move to Kohana though, because my other team member needs our code to fully use PHP5 features to their fullest extent. The problem is we have already coded over half of our project in CodeIgniter. Has anyone transferred code from CodeIgniter to Kohana before? Is it even possible to do, and how much effort will it take if so? Thank you in advance!

Update: From abi noda's answer, it looks like I really need to do a lot of code rewriting, but has anyone done this before ? Perhaps someone could point me some links? Yes, I think it is possible to do, but I don't know how long it'll take. I guess we're gonna keep this project as a CodeIgniter one, and move to Kohana as soon as our next project comes. Thanks for everything!

Answer 1

See Kohana's documentation - Migrating from CodeIgniter.

A smart fellow from #kohana IRC has informed me that a simple migration no longer exists. Kohana has changed substantially since forking from Codeigniter. They are very different frameworks now, so you would have to rewrite much of your code.

Answer 2

CodeIgniter works well on PHP5.

It is backwards compatible to PHP4, but there is no need to run it on PHP4.

What part of PHP5 is your team not able to use in CodeIgniter?