WordPress just had its first major upgrade for 2016. You can read the details about WordPress 4.5 at the WordPress blog.
So before you updated be sure to back up your database and files. Also take a look at the master list of issues to see if you’re using any plugins or themes that are having issues with WordPress 4.5.
If you have any problems after the update, my free WordPress guide has a troubleshooting section. I’d also be happy to help with any issues that you’re seeing on your site. Just contact me for assistance.