WordPress 4.3 has been in development since version 4.2 was released in April, and is due to be released sometime soon (tentatively August 18th). While it contains a number of improvements, some of them you won’t even notice. WP Beginner wrote a good article, based on a Beta version of 4.3, describing the upcoming changes. You can read their full article here.
If you’re one of our maintenance plan subscribers, you’ll be upgraded as soon as we make sure there won’t be any conflicts with your existing installation. If you’re not a maintenance plan subscriber, be certain that your blog is backed up prior to upgrading.