Well, it seems to be almost a weekly upgrade for WordPress version 2.8. Here we are at 2.8.4 which is another security upgrade. This one addressing a vulnerability where 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. Or in other words, do the upgrade!
With the integration of the automatic upgrade feature in WordPress version 2.7, there is no reason to put off these small incremental upgrades. If you are still using version 2.7 or older you should certainly upgrade but make sure to backup your database and the wp-content folder first. The database holds your settings and content. The wp-content folder holds your themes, plugins and uploads folder with any images you have added to posts. Another precaution is to check what plugins you have installed and the settings of those plugins.
If you are still using version 2.7 or older I suggest doing a manual upgrade. There are some hosting accounts that block access to the automatic upgrade feature for both WordPress and plugins. In this case, you will be stuck with the manual upgrade process. There are two outdated plugins that will probably produce errors when trying to update plugins and WordPress if you are using version 2.7 and above. For WordPress 2.7 and up the Automatic Upgrade plugin is no longer needed and should be deactivated and deleted. The other plugin is the One Click Plugin Updater which was used to automatically upgrade plugins. That feature is also now part of WordPress and the One Click Plugin Updater plugin should be deactivated and deleted. Trying to upgrade your plugins or WordPress with those two plugins active may cause errors.
You may also run into errors upgrading WordPress because of a combination of active plugins. In my case, I need to deactivate the first 7 plugins to get the automatic upgrade to work. So if you get an error you can try to deactivate one plugin at a time. I can’t stress enough to have a backup plan and make sure you have a recent backup before any core WordPress upgrade.
Here are a few posts to help you with your backup and upgrade:
Backup WordPress Database
Scheduled Backup Of Your WordPress Blog
WordPress Upgrade Error Allowed Memory Size Exhausted