$builder->add('my_date', array(
                'widget' => 'single_text',
                'attr' => array(
                    'class' => 'date-picker',
                    'size' => 10,
                ),
                'format' => 'dd-MM-yyyy',
                'required' => false,
                'input' => 'datetime',
                'constraints' => [
                    new GreaterThanOrEqual([
                        'value' => new \DateTime('01-01-2000'),
                        'message' => 'Invalid date value',
                    ]),
                    new LessThanOrEqual([
                        'value' => new \DateTime('31-12-9999'),
                        'message' => 'Invalid date value',
                    ]),
                ],
            )
        );