I customized a few sites. On my own i updated wordpress by diffing the (old) version and my site. Than i moved the folder away and put the new wordpress version and applied the patch. It seemed to work perfectly but binary files were missing (specifically plugin images). So i copied/overwrote the plugin folder.
I have a feeling i was lucky that it worked and i didnt do this right. Is diff/patch a good way to update wordpress? Should i be diffing my site from WP and apply it to the new version? Or should i diff the old version and new version than apply that patch to my site? There is also the issue about binary files. How do i update wordpress on customized sites?