Expected behavior Per documentation API : Using the "update" method you can change the values of the options. According to that , changing the value of the defaultDate should be achieved with the following code :

myDatePicker.update({defaultDate: newDate});

setting the "min" though works without issues (even though the "min" option is not mentioned in the documentated options which generally happens quite often in the documentation):

toDate.update({min: e.date});

Actual behavior Does not do anything

Resources (screenshots, code snippets etc.)

let fromDate = new mdb.Datepicker(document.querySelector('.datepicker-from'), {
  min: new Date(),
  format: 'yyyy-mm-dd'
});

let toDate = new mdb.Datepicker(document.querySelector('.datepicker-to'), {
  format: 'yyyy-mm-dd'
});

document.addEventListener('valueChanged.mdb.datepicker', (e) => {
  toDate.update({defaultDate: e.date});
});