Adds the ability to use custom templates for subcategories in wordpress

subcategory.php

<?php 
function new_subcategory_hierarchy() {  
    $category = get_queried_object();

$parent_id = $category->category_parent;

$templates = array();

if ( $parent_id == 0 ) {
    // Use default values from get_category_template()
    $templates[] = "category-{$category->slug}.php";
    $templates[] = "category-{$category->term_id}.php";
    $templates[] = 'category.php';      
} else {
    // Create replacement $templates array
    $parent = get_category( $parent_id );

    // Current first
    $templates[] = "subcategory-{$category->slug}.php";
    $templates[] = "subcategory-{$category->term_id}.php";
    $templates[] = "subcategory.php";

    // Parent second
    $templates[] = "category-{$parent->slug}.php";
    $templates[] = "category-{$parent->term_id}.php";
    $templates[] = 'category.php';  
}
    return locate_template( $templates );
}



add_filter( 'category_template', 'new_subcategory_hierarchy' );

?>