We recently updated a test server to the latest WordPress 3.6, but it immediately failed, missing a “revision.php” file. The resulting upgrade took down the entire website.
We are investigating the issue currently, but recommend that you do NOT update your WordPress to the latest version until we can find out more details.
Update: The problem appears sporadic. Some of our other test upgrades went flawlessly, and some were unable unpack the “revision.php” file for some reason. To resolve the broken instances, we downloaded the full WP 3.6 file, unzipped it and uploaded the WP-Includes files over-top of the broken version. We were then able to get back into WordPress Admin and force a “re-install” of WordPress.
