- Comments are turned off on pages by default.
- PHP-4 Style constructors have been deprecated to prepare for the release of PHP 7.
- Singular.php was added to the WordPress template hierarchy.
- Changes to customizer panels and sections.
- The old Distraction Free Writing (DFW) code has been removed.
- The code that powered the old theme preview has been removed.
- List tables have undergone API and UI changes, with the introduction of a primary column concept and easier subclassing.