The original Mercedes-Benz G-Class stuck around for four decades and was given multiple updates over the years to keep it fresh before a full redesign for the 2019 model year. It's not clear how long Mercedes plans to keep the current G-Class on the shelf before giving it a redesign, but it looks like the automaker will at least give the vehicle periodic updates in similar fashion to its predecessor.

Camouflaged prototypes for an updated G-Class have been spotted testing again. We can see revised fascias front and rear. The prototype is for the regular G-Class, but the updated AMG G 63 is also out testing.

We're told by our spy photographer that the dash was covered up, suggesting some changes inside as well. A key update inside should be the addition of Mercedes' MBUX infotainment system, which is used in every current Mercedes except the G-Class.

A bigger change is the likely elimination of the V-8 in the non-AMG versions of the G-Class, as an inline-6 and mild-hybrid combination is expected to serve as the replacement in the updated G-Class. A G 500 V8 Final Edition was launched overseas in June. The G 500 is badged as a G 550 in the U.S., and Mercedes is yet to say whether the G 550 will also swap the V-8 for the inline-6, but the move is likely.

A V-8 will remain in the AMG G 63, though it will also be teamed with a mild-hybrid system with this update. Though it's yet to be confirmed, a plug-in hybrid option may be added at a later date. A V-8-based plug-in hybrid system already features in AMG's S 63 E Performance and GT 63 S E Performance 4-Door Coupe. It pairs the familiar twin-turbocharged 4.0-liter V-8 with an electric motor at the rear axle for a combined output in the vicinity of 800 hp.

The updated G-Class is slated to debut next year as a 2025 model for the U.S. market. An electric EQG that will offer four motors is also out testing and is due around the same time.

Eventually, Mercedes will launch a baby G-Class. It's due later this decade with an electric powertrain.