For ActionSheetDatePicker, set disable before today.

ActionSheetDatePickerDemoViewController.swift

import UIKit

class ActionSheetDemoViewController: UIViewController {
  
  @IBAction func showDatePicker(_ sender: UIButton) {
    guard let actionSheetDatePicker = ActionSheetDatePicker.init(title: "Set date", datePickerMode: .date, selectedDate: Date(), doneBlock: {
      picker, value, index in
      /* doneBlock */
    }, cancel: { ActionDateCancelBlock in return }, origin: sender.superview!.superview) else {
      return
    }
    actionSheetDatePicker.minimumDate = Date()
    actionSheetDatePicker.show()
  }
}