Some updates for version 4.0.1B:
The problem with Polycom is that bugs reported are sinked into a "black hole" without any reply; some of them are fixed at the next version, some are not...
 
                        __Yehavi: 
 
2011/11/1 Yehavi Bourvine <yehavi.bourvine@gmail.com>
Hello,
 
  I've upgraded our Polycom phones from firmware 3.3.2 to 4.0.0 and have the following oddities:
 
- On shared lines the call lists are "mixed":
   - No calls are in outgoing calls.
   - answered incoming and outgoing calls are placed in incoming calls.
   - unanswered incoming and outgoing calls are placed in the answered calls.
- When the destination is busy there is no busy sign on the screen - the call is disconnected immediately
  and the phone returns to an idle state.
 
I've opened today a support call with Polycom, and will update when I get replies.
 
                        Regards, __Yehavi: