UPDATE: CarAdvice now understands that the i8 roadster is expected to be unveiled at the LA motor show in November, contrary to previous reports that indicated the plug-in hybrid drop-top would be revealed at September's Frankfurt motor show.

The upcoming 2018 BMW i8 roadster has been teased again by the Bavarian manufacturer on social media this week, ahead of a likely debut at the Frankfurt motor show next month.

A fleet of the plug-in hybrid drop-tops can be seen tearing up the roads in and around the European Alps, all wrapped in the eye-catching black and white camouflage that we have seen on previous prototypes (pictured).

BMW hasn't confirmed when it will reveal the i8 roadster, though it's been reported the final production version will make its debut at next month's Frankfurt motor show, ahead of a 2018 launch - the latter being confirmed by BMW's CEO last year.

The reveal of the convertible version should coincide with a rumoured mid-life update for the company's plug-in hybrid sports car, which should involve an uprated version of the i8's 1.5-litre turbocharged three-cylinder petrol engine - which is based on the unit used in several Mini models - along with a beefier electric motor and battery system.

Currently, the i8 pumps out a total of 266kW and 570Nm from its hybrid system, and recent reports suggest the refreshed model will push up to the 310kW mark. The current car's 7.1kWh battery is also set to get an upgrade to around 10kWh, which should improve the i8's "up to 37km" electric-only range.

If these rumours prove true, it would be logical to expect the i8's 4.4-second sprint from 0-100km/h to be improved as well.

The i8 roadster has already been previewed on two separate occasions, the first being the i8 Spyder concept in 2012 (above), along with the i Vision Future Interaction concepts in 2016.

Stay tuned to CarAdvice for more updates over the coming months.

Testing out its abilities on the curvy roads crossing the Alps. The #BMWi8 Roadster, coming in 2018, is in the final testing phase. #BMWi ______________________ BMW i8 Roadster All figures are preliminary: BMW i8 Roadster plug-in hybrid BMW eDrive: energy consumption (combined): 15,4 kWh/100 km. Fuel consumption (combined): 2,0 l/100 km, CO2 emissions (combined): 45 g/km. Fuel consumption is determined in accordance with the ECE driving cycle (93/116/EC), made up of approximately one-third urban traffic and two-thirds extra-urban driving (based on the distance covered). Further information about the official fuel consumption and the official specific CO2 emissions for new passenger automobiles can be found in the 'New Passenger Vehicle Fuel Consumption and CO2 Emission Guidelines', which are available free of charge at all sales outlets and from DAT Deutsche Automobil Treuhand GmbH, Hellmuth-Hirth-Str. 1, 73760 Ostfildern, Germany and on http://www.dat.de/angebote/verlagsprodukte/leitfaden-kraftstoffverbrauch.html

A post shared by BMW i. Born Electric. (@bmwi) on