function wc_update_220_attributes() {
	global $wpdb;
	// Update taxonomy names with correct sanitized names.
	$attribute_taxonomies = $wpdb->get_results( 'SELECT attribute_name, attribute_id FROM ' . $wpdb->prefix . 'woocommerce_attribute_taxonomies' );

	foreach ( $attribute_taxonomies as $attribute_taxonomy ) {
		$sanitized_attribute_name = wc_sanitize_taxonomy_name( $attribute_taxonomy->attribute_name );
		if ( $sanitized_attribute_name !== $attribute_taxonomy->attribute_name ) {
			if ( ! $wpdb->get_var( $wpdb->prepare( "SELECT 1=1 FROM {$wpdb->prefix}woocommerce_attribute_taxonomies WHERE attribute_name = %s;", $sanitized_attribute_name ) ) ) {
				// Update attribute.
				$wpdb->update(
					"{$wpdb->prefix}woocommerce_attribute_taxonomies",
					array(
						'attribute_name' => $sanitized_attribute_name,
					),
					array(
						'attribute_id' => $attribute_taxonomy->attribute_id,
					)
				);

				// Update terms.
				$wpdb->update(
					$wpdb->term_taxonomy,
					array( 'taxonomy' => wc_attribute_taxonomy_name( $sanitized_attribute_name ) ),
					array( 'taxonomy' => 'pa_' . $attribute_taxonomy->attribute_name )
				);
			}
		}
	}

	delete_transient( 'wc_attribute_taxonomies' );
	WC_Cache_Helper::invalidate_cache_group( 'woocommerce-attributes' );
}