WordPress 4.5 is now live! For a full recap of the changes in 4.5 visit this link.
The biggest changes you will notice when working in your site is the linking functionality in the editor. It is now an inline interface instead of the tradition popup:
Besides this change, most of the updates are behind the scenes and will not be noticeable to most users. Please be aware that this update has caused a lot of incompatibility issues. jQuery is breaking on many sites that were coded poorly. You will see this by noticing that your sliders are no longer working, dropdowns don’t show and parallax sections are not functioning correctly.
Remember to make a good backup before updating!!