Most of Jaguar's lineup are either all new or recently been redesigned. The only exception is the flagship XJ sedan. While it has been refreshed, there hasn't been any indication from Jaguar about what will happen next. Judging from comments by their North American product manager, it seems the fate of the XJ is very uncertain.
“We had a facelift with 2016, so it is approaching the end of its lifecycle,” Larsen said of the flagship XJ. “We’re looking at, you know, future opportunities of where that could possibly go,” said David Larsen to Motor1.
When asked if there was a next-generation XJ in the pipeline, Larsen said, “I can’t confirm or deny” anything related to that.
Sales of the XJ have been stagnant for the past few years. In 2016, Jaguar only moved 3,834 XJs. This put it ahead of the Genesis G90 (782) and Maserati Quattroporte (2,268), but way behind the Mercedes-Benz S-Class (18,803) and BMW 7-Series (12,918).
Jaguar might have decided to let the XJ follow in the footsteps of the XK coupe of slowly drifting away, putting their efforts into other models such as the F-Pace and other upcoming crossovers.