Instruction for updating aren't very clear.
It says to upload the new zpcore, themes folder and the index.php file. Where? Those files are, obviously, already on the server, do I overwrite them or do I create a new folder for the updated files?
What about all the customizations? If I overwrite files, won't those go away?
I ask because the last time I "updated" my zenphoto site, it went horribly wrong and the "update" completely hosed my site; I had to spend hours and hours rebuilding it from scratch, and it still doesn't work right(RSS is broken for example).