Yet another release in the WordPress 2.8 series, after those 2.8.1, 2.8.2, 2.8.3 versions, now the WordPress 2.8.4 is launched due to some security reasons. And the main advantage for us, is the core upgrade possibility that we have been seeing since the release of WordPress 2.8 release. That allows things to happen pretty easily, in just a few moments.
Here is the problem seen by the WordPress team -
Yesterday a vulnerability was discovered: a specially crafted URL could be requested that would allow an attacker to bypass a security check to verify a user requested a password reset. As a result, the first account without a key in the database (usually the admin account) would have its password reset and a new password would be emailed to the account owner. This doesn’t allow remote access, but it is very annoying.
The upgrade is highly recommended and it can be done by either downloading and installing, or else directly doing that from your wordpress admin panel, where the message might be already appearing if you are on WordPress 2.8.3 right now. You can upgrade with the Core upgrade option, where just a couple clicks are required. Everything else is automatic.

i had upgraded my blog
The new enhancements are very good and this version may be one of the best in its kind till now.
HEY i upgraded my blog that was really nice experience