Why with new bootstrap 3x-3.13 it doesn't work?
First of all, bootstrap is a theme not module.
You were using following code to above the main container(outside the image area as soon in your attachment):

function mytheme_preprocess_block(&amp;$variables) {
  $block = $variables['block'];

  // Create css id attribute based on the block's administrative name
  if ($block-&gt;module == 'block') {
    $custom = block_custom_block_get($block-&gt;delta);
    $id = strtolower($custom['info']);
    $variables['block_html_id'] = $id;
  }
}


If you were using this code in bootstrap theme's template.php, instead of a child theme, than after updating the theme the custom code will be no more there as the old files are replaced by new updated files.

So you need to add your code in new template file updated.