Hello

I have HCL v2.  1.  4 installed via Fantastico, and would like to upgrade to 2.  1.  7. 

Firstly, is this possible?

Is it better to do a clean install?

For upgrade, could someone please outline the steps I would need to follow. 

Cheers
Danielle

Edited to add:

Apache: 2. 2. 8
PHP: 5. 2. 5
MySql: 5. 0. 51a