Yes, it is a true. New NAV version has code name "Sicily". I think, new version will be ready in early 2014, but I expect Beta version in 2013Q3.
Because all of us expect beta, Direction EMEA moved the conference from April to September, to be in line with the new NAV version.
I am localization partner, and we are not a happy about this roadmap; we have to have a team that will work on localization all the time. But, this is a plan.
"Sicily" will introduce a new Windows 8 interface. And, just as NAV 2013’s interface conformed to Office 2010 standards; "Sicily" will be closely tied to Office 2013.
I heard, that there will be less new functionality (cash management e.g.) and more tchnical (new client, better hosting model, a lot more integration with Office 2013 and Office 365...).
Also, I heard from MS employees that upgrade will be much simpler. Maybe someone else has more information.