From the WordPress Dashboard home screen,

go over to the left hand side, and click "Updates."

And you are going to see any updates that are available for plugins or themes,

also any updates that are available to the WordPress core.

You can check at anytime for any updates,

and for demonstration purposes, I'm just going to re-install WordPress, and you can see that it is downloading now,

checking the update, it verifies, does the install, and then brings you to, after it's done,

then brings you to the welcome screen of your point release,

this is WordPress version 4.2.2.

And if you go back over and click on the "Dashboard" and then "Updates,"

you can see that it has been re-installed at this point.

You can also download the zip file,

and you can go to your "Update Plugins" page,

and then you can return to the "WordPress Updates."

You can see now there are no plugins that need updated.

The themes that come with default install of WordPress can be updated,

and you will see this message that the site is in "Maintenance mode."

If somebody happens to go to your website during this time,

they will see a message that the site is being placed in "Maintenance mode" for an upgrade

and will be available shortly.

Usually it just takes a few seconds up to a few minutes,

depending on the speed of your server.

So returning to the Updates page, you will see that everything is up to date now.

And point releases and security releases are very important to update,

as well as plugins and themes updates.