How to upgrade from old version to new one

[eluser]JasmineFlower[/eluser]
Hi,

I am using codeigniter 1.7.3. I need to upgrade from 1.7.3 to 2.0.1. How to upgrade? copy the files from old version system folder to new version folder? or copy new version system files to old version system folder files?

[eluser]InsiteFX[/eluser]
CodeIgniter Upgade

InsiteFX