Apple's CarPlay, a platform bringing iOS apps and Siri to in-car systems, hasn't even arrived yet, but Mercedes is apparently planning to extend it to older vehicles via an after-market product.

Apple's CarPlay, on display at the Geneva International Motor Show this week , will begin appearing in vehicles later this year, bringing the iOS interface into the vehicle's infotainment screen where iOS apps such as phone, messaging, navigation as well as some third-party apps share space with the vehicle manufacturer's own content and apps.

Ferrari will provide CarPlay integration in its new FF model, Volvo is doing the same for its XC90 SUV, to be released later this year, and Mercedes will have it installed in its new C-Class vehicles, most likely alongside Android and MirrorLink integration.

But what about CarPlay for all the owners that bought last year's C-Class or, in Volvo's case, last year's model of the XC90? Or is CarPlay only for new cars?

According to 9to5 Mac, Mercedes has confirmed it will offer an "after-market solution by the end of the year", which it speculates could come in the form of a dealer-installed accessory, similar to after-market Siri Eyes Free integration offered by some Honda dealerships.

However, ZDNet contacted Mercedes UK and was told by a spokesperson that it could not confirm the car maker would offer an after-market solution yet, since "we don't have have any firm dates for its arrival yet".

Volvo isn't certain yet whether it will offer a service to integrate CarPlay for vehicles that have already been sold.

"We have not yet decided if -- or in that case, when -- we will be offering an aftermarket solution for CarPlay, but we are measuring consumer interest following the announcement last week," David Holecek, Volvo Car's connectivity brand and marketing manager told ZDNet.

Volvo last year worked with Neonode to build an Android-based infotainment system with a 7-inch display called Sensus Connected Touch. Holecek said the way forward for Volvo infotainment displays was portrait over landscape.

Mercedes this week stressed that Android integration would be available as soon as Google's Android infotainment system was ready.

According to Volvo, Apple CarPlay allows connection of an iPhone to the car through a Lightning cable. The connection is based on a streaming H.264 video feed that returns user input from the touchscreen.

Ferrari similarly had a wired connection for its demo in Geneva this week, according to Engadget's hands-on. It noted that Volvo is working on a wireless connection too.

Countries currently listed for CarPlay distribution include Australia, Canada, France, Germany, Hong Kong, Italy, Japan, Mexico, Republic of Korea, Spain, Switzerland, UK and USA. Despite Volvo's early support, Sweden, as with the rest of the Nordics, are off the list.

Other car manufacturers that plan to release CarPlay in the future include BMW, Chevrolet, Ford, Jaguar, Kia, Landrover, Mitsubishi, Nissan, Opel, Pegeot-Citroen, Subaru, Suzuki, and Toyota.

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