From 2.x-dev (2009) to 2.x-dev (2011)

I use the event module version 6.x-2.x-dev (2009 August 28). I see no major difference with 6.x-2.x-dev (2011) and do not know if there is an issue that would make integrating the 2011 version important or worthwhile (i.e. as I have some customization set inside the 2009 version).

I see two differences between the two versions :

- in the module file as such :
2011 writes (line 736): 'class' => strtolower("$month_name ". $weekdays[$x]['day'] . ($cur_date == $today ? ' today' : '') . ($cur_date['day'] == $date['day'] ? ' selected' : '')),
2009 writes: 'class' => strtolower("$month_name ". $weekdays[$x]['day'] . ($date == $today ? ' today' : '') . ($cur_date['day'] == $date['day'] ? ' selected' : '')),

- In my 2009 version, I manually added :

function event_views_api() {
  return array(
    'api' => 2,
  );
}

- the 2009 version has the extra files :
event_handler_field_date.inc
event_handler_filter_date.inc

Question (support) : is there a major reason (bugs, quirks, compatibility with php 5, etc.) why I should convert to the new version ?

Thanks