Patch X.5 and X.55 have generally been the last content and story updates of an expansion.

The only reason I could see them doing any exception is the fact that they might be pushing out towards a new big overarching plot and they might need more time than usual for that... Since it hasn't exactly even started yet as of 6.3.

But we do still have 3 patches (6.4, 6.5 and 6.55), and I assume patch 6.4 with Golbez will reveal the actual plothook for the next story arc through some very intense Exposition Dumping, either before or after we beat him.