I run raptorsrepublic.com which uses WordPress with some pretty heavy customizations here and there so every time WordPress releases an upgrade I’m very wary of doing it because I just don’t know how it’ll effect the platform. Partial file copying with FTP can really throw you a curveball and if one file gets corrupted it’ll take you hours to find out which one.
I think the best way of upgrading WordPress installations is by only copying files that changed over patch releases (e.g.: 2.8.2, 2.8.3 and 2.8.4). If there’s a database change things get a little more complicated but in most patch releases that’s not the case.
The way you find out what files were changed is by accessing the WordPress SVN repository and running the svn diff command. Here is the commands one need to run and the output that follows it. I’m running this on a Linux box with SVN installed. You could also do it in windows if you download the binaries.
svn diff --summarize http://core.svn.wordpress.org/tags/2.8.3/ http://core.svn.wordpress.org/tags/2.8.4/ M http://core.svn.wordpress.org/tags/2.8.4/wp-login.php M http://core.svn.wordpress.org/tags/2.8.4/wp-includes/version.php M http://core.svn.wordpress.org/tags/2.8.4/readme.html
This means three files changed between the two versions as M stands for modified. That value could also be A for added and D for deleted. If you’d like to see what the actual changes were just get rid of the
--summarize part. I copied these three files over to my WordPress installation and I’m done!