So what's new in Wordpress 4.5? Many of the changes relate to the theme customiser. This is the "as live" view of your site that you get to via the Appearance -> Customise menu item. You will be able to see responsive views within the customiser, so you can see how your changes affect the site on tablets and mobiles, as well as on the desktop. Support is also going to be added for a theme logo within the customiser.
Other changes include inline link editing, improvments to the process of moderating comments to your blog, and improvements to the way images are saved reduce their file size while retaining their quality.
As usual, there's also a series of changes that are largely of interest to developers only that will offer improvements to the process of building a website in Wordpress.
As ever, we recommend a full backup of your Wordpress website before going ahead with the upgrade. While the changes should be backward compatible, there's always the odd case in which the upgrade doesn't go as expected. In these cases, it's very useful to have a version to roll back to, rather than having to try and work out what's wrong while your live website is broken.