Disable PHP Deprecated Warnings in Wordpress

When moving a WordPress site to a new server running the latest version of PHP5 (i.e. > 5.3), PHP Warnings may appear.

The following code will turn off these warnings even when WP_DEBUG is set to true

In your wp-includes/load.php

<?php

function wp_debug_mode() {
 if ( WP_DEBUG ) {
  error_reporting( E_ALL ^ E_NOTICE ^ E_USER_NOTICE ); // changed from error_reporting( E_ALL );
 
  if ( WP_DEBUG_DISPLAY )
   ini_set( 'display_errors', 1 );
  elseif ( null !== WP_DEBUG_DISPLAY )
   ini_set( 'display_errors', 0 );
 
  if ( WP_DEBUG_LOG ) {
   ini_set( 'log_errors', 1 );
   ini_set( 'error_log', WP_CONTENT_DIR . '/debug.log' );
  }
 } else {
  error_reporting( E_CORE_ERROR | E_CORE_WARNING | E_COMPILE_ERROR | E_ERROR | E_WARNING | E_PARSE | E_USER_ERROR | E_USER_WARNING | E_RECOVERABLE_ERROR );
 }
 if ( defined( 'XMLRPC_REQUEST' ) )
  ini_set( 'display_errors', 0 );
}

Reference: ‘PHP Deprecated’ warnings on every screen