Disklavier

Hi:

     I bought a Mark IV in November, 2006 and understand that there is 
a firmware upgrade available.  I sent an e-mail two weeks agao to 
Yamaha requesting confirmation that an upgrade exists and to ask for a 
copy but have not had a reply.  Last week, i sent an e-mail to the 
dealer from whom i purchase the piano and again received no reply.  
Does anyone know if there is an upgrade available and what i have to do 
to get a copy? Thanks,

                        Joe