The old days of a scary update have pretty much gone thankfully. WordPress is an extremely stable framework, and extremely well supported with regular updates. Some updates are more important than others, but I strongly recommend that all Redback Graphics clients with WordPress sites update their WordPress to Version 4.0.1 as soon as possible.
Make sure to do a backup of your site prior to updating.
See article creating a website backup.
To update your WordPress is very simple. Login to your Dashboard, and at the top centre of the Dashboard home screen you will see “WordPress 4.x.x is available! Please update now.”
Click on “Please update now”.
The next screen will offer the opportunity to “Update Plugins” and “Update Themes”. DO NOT update these at this time, only choose “Update Now” button to update the WordPress.
Importantly, WAIT and watch as the WordPress enables Maintenance mode (site offline for a few seconds), then disables maintenance mode and your site is back online. Dashboard will then log you out and ask you to login again, to use the updated Dashboard.
If you have any problems please let me know asap.