Depreciated settings & CSS question

Hi all,

I am currently using the following code to style the reaponse messages

.wpcf7-form .wpcf7-response-output.wpcf7-validation-errors {
  color: #D8000C;
  background-color: #FFBABA;
  display: none;
  border: 0;
  padding: 10px;
}

.wpcf7-form .wpcf7-response-output.wpcf7-mail-sent-ok {
  color: #4F8A10;
  background-color: #DFF2BF;
  display: none;
  border: 0;;
  padding: 10px;
}

div.wpcf7-mail-sent-ok:before,div.wpcf7-validation-errors:before {
    font: 26px/30px FontAwesome;
    margin-right: 16px;
    vertical-align: middle;
}
div.wpcf7-mail-sent-ok:before {
    content:'\f00c';
}
div.wpcf7-validation-errors:before {
    content:'\f057';
}

Which works very well. My question is this, considering certain things such as on-sent-ok are due to be abolished by the end of this year, what, if any changes will I need to make to my css in order to achieve the same effect?

Any help appreciated. Thanks