$crud->unset_bootstrap();with the above one line of code you are actually removing the calls for:
$crud->unset_jquery();you can remove the call of the jquery from grocery CRUD.
Bootstrap V4 is still in alpha version so you need to be aware that some CSS class names may change at the future.
Reasons to buy the version 4:
Notice 2: If you want to make sure that the grocery CRUD doesn't look broken, we are strongly recommending to use the bootstrap version that is coming with the theme
Bootstrap V3 is simply the latest stable release of twitter bootstrap that we all know.
Reasons to buy the version 3: