Finally! I have not received a mail from polo yet, but withdraw and deposit are open again.
Polo wrote this on the site:
All NAV balances have been migrated to the new blockchain.
Posted by busoni@poloniex at 2016-07-11 13:13:27
Happy trading!
Nice! NAV is back to business!
Too bad, the volume of it in Poloniex is too low. I hope the recent news do drive it increase.