Bootstrap 4 + Parsley JS

form.html

  $("#parsleyForm").parsley({
    errorClass: 'has-danger',
    successClass: 'has-success',
    classHandler: function(ParsleyField) {
        return ParsleyField.$element.parents('.form-group');
    },
    errorsContainer: function(ParsleyField) {
        return ParsleyField.$element.parents('.form-group');
    },
    errorsWrapper: '<span class="text-help">',
    errorTemplate: '<div></div>'
  });

This is for Bootstrap 3

For Bootstrap 4 use this
$("#my-form").parsley({
errorClass: 'is-invalid',
successClass: 'is-valid',
errorsWrapper: '',
errorTemplate: '',
trigger: 'change'
})/* If you want to validate fields after page loading, just add this here : .validate()*/;

See the fiddle
https://jsfiddle.net/djibe89/tu0ap111/

any update for Bootstrap 4.1? So far I have this which works fine but does not work with checkboxes.

errorClass: 'is-invalid',
successClass: 'is-valid',
errorsWrapper: '<span class="invalid-feedback"></span>',
errorTemplate: '<div></div>'

any update for Bootstrap 4.1? So far I have this which works fine but does not work with checkboxes.

errorClass: 'is-invalid',
successClass: 'is-valid',
errorsWrapper: '<span class="invalid-feedback"></span>',
errorTemplate: '<div></div>'

@SimonFricker I'm using Bootstrap 4.4.1 and this worked very good to me:
{ errorClass: 'is-invalid', successClass: 'is-valid', classHandler: function (ParsleyField) { return ParsleyField.$element; }, errorsWrapper: '<div class="invalid-feedback"></div>', errorTemplate: '<div></div>' }