WordPress 4.9 deprecated the WP_Customize_New_Menu_Control and WP_Customize_New_Menu_Section PHP classes and wp.customize.Menus.NewMenuControl JavaScript class. The Core Team initially planned to remove them entirely in WordPress 5.0. Deprecated items Given how much time has elapsed since then, WordPress 5.4 leaves in place WP_Customize_New_Menu_Control and WP_Customize_New_Menu_Section to prevent potential backwards compatibility issues. 5.4 also formally deprecates them using _deprecated_file() and _deprecated_function() calls. As a reminder: _deprecated_file() … Continue reading Formal deprecation of some unused Customizer classes in WordPress 5.4