Bootstrap v2 had two classes (has-success and has-danger) that were changed in bootstrap 4 and removed in bootstrap 5 https://getbootstrap.com/docs/5.0/forms/validation/

From my understanding we can therefore remove the use of those classes in https://github.com/joomla/joomla-cms/blob/4.0-dev/build/media_source/system/js/fields/validate.es6.js and maybe other changes can be made as well. (valid/invalid??)

The scss may also need updates as a result. For example we dont need to define valid/invalid in both files

• administrator\templates\atum\scss\blocks_form.scss
• administrator\templates\atum\scss\vendor\bootstrap_form.scss

bonus is that we get much nicer styling