Porsche's second-generation Panamera is set to come in for a subtle facelift as it reaches the midway point in its life cycle, as evidenced by camouflaged prototypes spotted in the wild.

The latest prototype is for the Panamera's Sport Turismo wagon body style. Earlier testers showed the regular liftback sedan.

The current Panamera arrived in 2016 as a 2017 model, so we'll likely see this updated one around the end of 2020 as a 2021 model.

2021 Porsche Panamera Sport Turismo facelift spy shots - Photo credit: S. Baldauf/SB-Medien

2021 Porsche Panamera Sport Turismo facelift spy shots - Photo credit: S. Baldauf/SB-Medien

The prototypes have new fascias front and rear. The taillights have also been tweaked and feature a new design for the center strip joining the individual light clusters, which will likely end up being similar to the design used on the latest versions of Porsche's Cayenne and Macan SUVs.

We should also see more power added to the various models in the Panamera line, which is usually the case with any Porsche mid-cycle facelift.

The range currently starts with a 330-horsepower 3.0-liter turbocharged V-6 in the base Panamera and tops out with a 680-hp 4.0-liter twin-turbocharged V-8 and plug-in hybrid setup in the Panamera Turbo S E-Hybrid.

2019 Porsche Panamera GTS Sport Turismo first drive

2019 Porsche Panamera GTS Sport Turismo first drive

One possibility is the addition of a 48-volt mild-hybrid system and perhaps even the use of electric compressors.

More and more automakers are starting to introduce mild-hybrid systems. This is essentially a beefed-up starter motor that can aid the engine during high loads and recover energy under braking and coasting. In some cases, it can also power an electric compressor that helps build boost pressure in force-fed engines before revs rise and a conventional supercharger or turbocharger takes over. Some models from Porsche sister brand Audi already feature the technology.

Porsche is also known to be testing a hardcore Panamera with a more extreme aerodynamic package. There's been no official confirmation of production but there are rumors the car could arrive this year as a limited-edition model celebrating the 10th anniversary of the nameplate.