Thank you all for your replies.

The version installed is the latest so there is no problem with this.

Also there are not modifications in the code, but several custom (not file) fields are used, globals, plugins and the multilanguage plugin.

The aim is also to minimize downtime so making a new installation, then installing plugins, copying .def files and template files (which ones? or all of them?) and importing the database seems safer than copying over and then starting testing the paths that failed to replace correctly. Does this order of actions look correct or not?

Any suggestions?