These photos don't tell as anything about the new XJ's design, but Jaguar's people are talking about a reinterpretation of the XF's styling in a larger package, meaning that the new XJ will look as much as the current model as the XF did with the S-Type.
The next XJ is said to use a re-engineered version of the current model's all-aluminum chassis riding on a similarly sized wheelbase as the current car. Once again, Jaguar will offer the XJ with a choice of standard or long wheelbase models while the engine range will include a 3.0-liter V6 diesel in 240HP and 275HP specifications and three gasoline units, a 238HP 3.0-liter V6 and a 5.0-liter V8 available in naturally aspirated and supercharged forms with 383HP and 510HP respectively.