Catch 404 after changing permalink structure from /%postname%/ to /%category%/%postname%/
That happens because WordPress reads your old post name as category name now – and it cannot find that category. Solution: filter 404_template and try to find the post and its permalink. Then redirect. <?php # -*- coding: utf-8 -*- /* Plugin Name: Redirect to category */ add_filter( ‘404_template’, ‘t5_redirect_to_category’ ); function t5_redirect_to_category( $template ) … Read more