Based on what they did last year, next release of dates should be around mid-April with schedules for travel through mid-September. And then the end of May the schedules should open for the rest of September and most of October.
According to folks on flyertalk though they waited so late the last time and released all the way till the end of August. They also stated that they will try on future releases to not have less than 120 days inventory in the schedule.
So I'm guessing mid-May and they'll go out through the end of October.