I'm doing some tests as I just discovered the new 'subscribemode' 

attribute. It seems I can't send 'subscribe parent::myobject'. 

Although the documentation does not mention this clearly (imo), should 

I assume one can only subscribe objects placed in the same patcher or 

I'm doing some tests as I just discovered the new 'subscribemode'  
attribute. It seems I can't send 'subscribe parent::myobject'.  
Although the documentation does not mention this clearly (imo), should  
I assume one can only subscribe objects placed in the same patcher or  
below ?

psto-subscribing-objects-in-parent-patcher

Correct. The pattrstorage 'greedy'ness still applies in subscribe modes -- you can't subscribe upwards.

psto: subscribing objects in parent patcher