Development has moved on to some exciting new features for the next major release, but an important security issue was brought to our attention which required an update for our users. The problem is not yet public but you should update your blog as soon as possible to 1.5.1.3. If you are unable to do upgrade in the short-term you may protect yourself by deleting the xmlrpc.php file from your WordPress directory.

Its important that you upgrade to the latest version…., going by my past experience