Deprecated calls for form_javascript

[CPASimUSante]

I'm using your bundle in a symfony (2.8) project, where it works fine, but i'm having deprecated calls in the logs (which are not blocking yet, but who knows if i upgrade my package versions) which i wish to get rid of :

Using an instance of "Twig_Function_Method" for function "form_javascript" is deprecated since version 1.21. Use Twig_SimpleFunction instead

In my form i use, as you indicate :

...
    {{ form_start(form, {'method': 'post', 'action': path('mypath'), 'attr': {'class': ''}}) }}
        {{ form_widget(form) }}
        {{ form_javascript(form.sessionDateStart) }}
        {{ form_javascript(form.sessionDateEnd) }}
    {{ form_end(form) }}

I looked around a little, and i saw that in mablae/datetimepicker-bundle/src/Twig/Extension/FormExtension.php

    public function getFunctions()
    {
        return array(
            'form_javascript' => new \Twig_Function_Method($this, 'renderJavascript', array('is_safe' => array('html'))),  // twig <= 1.11
        );
    }

maybe it should be replaced by something like :

new \Twig_SimpleFunction('form_javascript', array($this, 'renderJavascript'), array('is_safe' => array('html'))),

But ovbiously, i don't know if there would be full backward compatibility

Thanks