You all know why:
Deactivate all the plugins before you upgrade.
Go to ‘Manage’, then to ‘Export’, then click on the button which says ‘Download Export File’.
Upload all the files and folders, except the wp-content, the reason being it has all your plugin and theme files, so there is no need to replace them as it is [...]
Matt Mullenweg, has declared the entire 2.1.1 version dangerous as cybercrooks gained user-level access to one of the servers controlling Wordpress.org and altered two files that would allow remote PHP code to be executed.
Users who visit websites running on the same server as the compromised WordPress software are not likely to be at risk, but [...]