We were there this year during that time frame and original schedules were about 6 months out - I think a little sooner, because I had something to work from when making 180 day dining reservations. HOWEVER, I don't know if this year was odd or typical, but park hours and the days of EMH changed within about 6 weeks or so. Party days did not change, though.
There were lots of threads here of people complaining about the change to their plans. It bothered me and had I known the final schedule, I'd likely have planned a few different park days, however I stuck with my original plan and it was still lovely. Long-winded way of saying: plan, but be flexible! Expect changes from Disney.