Update Prestashop version 1.6.1.16 to latest version 1.6 stable (and NOT 1.7)

Update Prestashop version 1.6.1.16 to latest version 1.6 stable (and NOT 1.7) -->We have done a copy (subdorectory) on live server, and we tried one click module upgrade, but didn't work, after 2 hours wait, we get a server error because db is BIG (aroound 1 giga) So you need do other way more professional than this module one click upgrade which NEVER works -->It is a simple website, theme is not important as we will ourself install a new theme later