Konu güncel şöyle bir hata alıyorum

Deprecated: Function create_function() is deprecated in /home/siteadı/public_html/wp-content/plugins/revslider/includes/framework/functions-wordpress.class.php on line 257

Warning: Cannot modify header information - headers already sent by (output started at /home/siteadı/public_html/wp-content/plugins/revslider/includes/framework/functions-wordpress.class.php:257) in /home/siteadı/public_html/wp-content/plugins/siparis-panel/index.php on line 12

Warning: Cannot modify header information - headers already sent by (output started at /home/siteadı/public_html/wp-content/plugins/revslider/includes/framework/functions-wordpress.class.php:257) in /home/siteadı/public_html/wp-admin/includes/misc.php on line 1126

Fatal error: Uncaught Error: [] operator not supported for strings in /home/siteadı/public_html/wp-content/themes/betheme/functions/builder/back.php:918 Stack trace: #0 /home/siteadı/public_html/wp-content/themes/betheme/functions/meta-portfolio.php(477): mfn_builder_save(2703) #1 /home/siteadı/public_html/wp-includes/class-wp-hook.php(288): mfn_portfolio_save_data(2703) #2 /home/siteadı/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #3 /home/siteadı/public_html/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #4 /home/siteadı/public_html/wp-includes/post.php(3673): do_action('save_post', 2703, Object(WP_Post), true) #5 /home/siteadı/public_html/wp-includes/post.php(3746): wp_insert_post(Array, false) #6 /home/siteadı/public_html/wp-admin/includes/post.php(399): wp_update_post(Array) #7 /home/siteadı/public_html/wp-admin/post.php(200): edit_post() #8 {main} thrown in /home/siteadı/public_html/wp-content/themes/betheme/functions/builder/back.php on line 918