Umberto, the new gsx version with SODE will be 1.9.x or the new gsx with a cost for actual users?
GSX has been released 3.5 years ago, and all the countless updates to it has always been free as of today so, at a certain point, we'll have to consider to release a paid update, which will obviously have a favorable update price for existing users.
But at this point, we haven't decided yet which future new features will be free, and which will require a paid update. When we have something to announce, you'll here it first.
Of course, I'm only referring to major new features. Small updates, bugfixes, new supported planes and airports, will always be free.