PH version, performance, pending support request

I've been playing with the distribution for some time, unfortunately there's been delays in the original project due to lack of content provisioning.

Meanwhile I discover new things and of course, have new questions. Still looking forward to see documentation on design customization, especially around and about color schemes, radix/grid tuning and more.

I've manage to sort out most but one remains that I've asked about here. Could someone please shed some light on why I am not getting the expected results? Am sure I've overlooked something obvious (again).

I notice that running PHP 5.4 gives much better performance but it cannot be done without errors. One of which is this:

Strict warning: Only variables should be passed by reference in restaurant_reservation_send_update_status_mail() (line 189 of /profiles/restaurant/modules/restaurant/restaurant_reservation/restaurant_reservation.module).

Switching to PHP 5.3 resolves the error message. I am sure there are other things not yet discovered.

So my main question is; when will the distribution be ok to run PHP 5.4?

And while at it, when will there be an update with the latest Drupal version? Or, is it safe to upgrade the current install to the latest Drupal core?

Thanks!