Full exchange launch of both version (centralized and decentralized) will be between Q1 and Q3 next year? Why there is no exact date (month or at last exact quarter) ?
The devs usually do it in order to have some additional time for fixing anything going wrong or not according to their original plan.
But eact date (at last exact month or even quarter) giving investors some of understanding when to except important things in their development and when to except price growing...
They will probably narrow down the the date as time passes. Right now it makes no sense to say the launch will be on September 1, 2019 for example.