Php version for codeigniter 1.7.2

Question

I have working code of codeigniter. It is already deployed by someone else.

When I am trying to run it locally, facing lot of problems in running them.

My current php is php5 (5.3) I think it will work well if I change php version to some older version.

What version it is ?

Because, I tried putting the applications directory into a newversion of codeigniter(2.2). I spent time changing classnames (to CI_) and changing constructors. Some parts working but some parts not working. Upgrading is not my intention, but just runing it is my intention. So, want to try downgrading version of php which might be simple.

Answer 1

according to this , PHP 5.2.11 was released in September 17, 2009

according to this , CI 1.7.2 was released in September 11, 2009

Anyway, according with the first link, PHP 5.3.0 was released in June 30, 2009