Important: Update your themes when updating to WordPress 4.5

WordPress 4.5 includes breaking changes to underlying libraries that our themes use, the galleries in particular. When updating to WP 4.5, you will also need to update your theme to avoid any issues as all affected themes had an update published on 4/12.

If you have registered your theme, the update will show as available in your WordPress updates page and you can apply the update using WordPress’ update system. If you have NOT registered your theme, you will either need to register it so you can automatically update using WordPress, OR you can manually update (instructions here).