WordPress 5.8 is here. Widgets editor is now block-based widgets editor by default. This is huge improvement release and this gives users new ways to customize their sites using the rich library of core and third party blocks. Existing widgets and third party widgets will continue to work and can be used alongside blocks. In most cases, users might need to restore the classic widget editor and disable the widget block editor.
Here are the three ways to restore classic widget editor:
Using the Classic Widgets plugin
Classic Widgets is an official plugin maintained by the WordPress team that restores the previous (“classic”) WordPress widgets settings screens. It will be supported and maintained until at least 2022, or as long as is necessary.
Using a filter
The use_widgets_block_editor filter controls whether or not the Widgets Block Editor is enabled.
A site administrator may include the following PHP code in a mu-plugin to disable the Widgets Block Editor.
A site administrator may add their own function. For example, the Widgets Block Editor is disabled for a specific user.
Using remove_theme_support function
Themes may disable the Widgets Block Editor by calling remove_theme_support( ‘widgets-block-editor’ ).
A site administrator may add the following PHP code in functions.php file of the child theme.