Reply To: I had same changes after the update

i found the problem i added this code function.php on child theme . But how can i do everytime i do an update it wont be replace?

function custom_wc_ajax_variation_threshold( $qty, $product ) {
return 150;
}

add_filter( ‘woocommerce_ajax_variation_threshold’, ‘custom_wc_ajax_variation_threshold’, 10, 2 );