Inside WordPress, when there is an update available it tells you at the top of the page, and gives a link to update.
This makes it easy to update your version of WordPress yourself – you will see this message if you have administrative access to your WordPress. Otherwise it will say something like “Please contact your administrator about this….”
WordPress will then automatically upgrade to the new version, within a few minutes at most. However, just like any automated upgrade, if it isn’t done in the right way it can shatter your website into a million pieces, and be very costly to repair.
The reason is that a WordPress updates the core software. It doesn’t take into consideration any incompatibilities; that when your theme design was made it isn’t going to work with the latest version. Or that you have 50 plugins, none of which work with the new version. Or that one of your plugins is made in such a way that it will actually corrupt your website database that contains all your website content, because of some particular bit of code in it.
The older your website and the more stuff on it, the more likely it’s going to have problems.
We recommend you take the following steps when upgrading your version of WordPress:
1) Make a full backup of the website itself, and of the mysql database too.
2) Get a professional to help you. It’s easy to press a button to upgrade something, but it may have unintended consequences. Not using a professional could be more costly to your business than using one.
3) Ideally duplicate your website and test the new version on it. If it breaks, you know that the live one is going to have problems and requires further investigation.
WordPress makes it easy to upgrade, but again it’s only upgrading the core software. There’s so much more to WordPress that if you don’t take into consideration the more complex factors you’ll end up with a pile of mush.