A facelifted version of Audi’s A8 flagship sedan is due to be revealed at this September’s 2013 Frankfurt Auto Show, and we have a new batch of spy shots of a prototype as it undergoes final evaluation.

The facelifted A8 is expected to arrive on the market early next year as a 2015 model, and most of its upgrades will focus on new technology.

As these spy shots reveal, the updates to the car’s styling will be minimal.

In true Audi tradition the visual changes consist of subtle tweaks to the lights, grille and bumpers. We’re not complaining, since the current A8, particularly in its sporty S8 guise, is one the most elegant luxury sedans on the market.

For models sold outside the U.S., the 2015 A8 will feature Audi’s latest Matrix LED headlight technology. This will allow drivers to leave the high-beam permanently on as the Matrix LED headlight, which uses an array of individually controlled LEDs, automatically splits the light beam to block out sections that may blind other motorists. Unfortunately, U.S. regulations prohibit their use locally.

Audi Matrix LED headlight technology

Audi Matrix LED headlight technology

The interior of the 2015 A8 facelift is likely to receive its own set of subtle updates, along with some new technologies including the latest version of Audi connect Internet services, a modular infotainment system and possibly a redesigned instrument cluster.

It’s not clear if Audi will be planning significant updates to the powertrain lineup, although we’re still unlikely to see the A8 Hybrid offered in the U.S. anytime soon. The current 3.0-liter and 4.0-liter TFSI units should carry over largely unchanged, as should the range-topping 6.3-liter W-12. A 240-horsepower 3.0-liter TDI diesel was just added for the 2014 model year, so this unit will almost certainly carry over with the same spec.

While the A8 will be facing some serious competition from a new Mercedes-Benz S-Class due out later this year, the changes should keep the car looking fresh until a completely redesigned model, possibly based on Porsche's MSB platform and with autonomous driving capability, launches a couple of years further down the track.

Stay tuned for updates as development progresses.

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