WordPress 5.3 old style admin buttons and UI plugin
Revert back to WordPress pre-5.3 “Kirk” style of the admin UI: buttons, borders, form elements.
The plugin styles the Wordpress 5.3+ admin panel back to how it was before the 5.3 update. You can now both update Wordpress to 5.3 and benefit from its code updates, while also retaining all of the previous version’s UI styles.
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