A must have stable release of WordPress (Version 2.5.1) of is released with over 70 fixes. WordPress 2.5.1 focuses on fixing the most annoying bugs and improving performance. It is recommended that everyone update immediately, and particularly those who have open registration to their blog.
Some of the highlighted fixes are:
- Performance improvements for the Dashboard, Write Post, and Edit Comments pages.
- Better performance for those who have many categories
- Media Uploader fixes
- An upgrade to TinyMCE 3.0.7
- Widget Administration fixes
- Various usability improvements
- Layout fixes for IE
It is recommended that you back up your Wordpress database and files before updating just in case if you messed up with the update process you can always restore your database from backup. For information on how to back up a WP database just check out this post. Another easier way to backup is to install the WordPress database backup Plugin from the link given below.
If you are facing any problems regarding the update you can always check how to Upgrade WordPress.
Links: Download Latest Version of WordPress | List of Fixes | How to Backup WP Database | Download WordPress Database Backup Plugin







