How to use multiple themes in codeigniter like wordpress
Hi
Very hard to give this answer because your question is very out of range. :)But I will try my best to do this.
Many way to build different themes put in CI
1) Use of CMS in codeigniter like
2) Second way to do this things the easy way is to build your dynamic system as per your recruitment.
Also easiest way is to build your site in wordpress.
Although the library has it years(newer php version may scream error about &=, just delete & ) you can use https://github.com/philsturgeon/codeigniter-template - it uses theme concept. But you have to build database layer for themes usage logic. And if you know, which theme your site is using, then you just use method of the library: $this->template->set_theme($my_current_theme)
If you like a complete tutorial, check out this linkhttp://www.roytuts.com/using-template-in-codeigniter-3/. This is just an example, however and there's many more out there.
I agree with cssBlaster21895, that library can still be made to work for modern PHP versions. I just adjusted a few things and that made the errors disappear.