Detroit automaker Ford enabled Siri Eyes Free integration for more than five million car owners with the release of a Sync infotainment system software update on Thursday, an upgrade compatible with cars dating back to the 2011 model year.

Ford initially revealed the Sync version 3.8 update with Siri Eyes Free compatibility in October, but held off on a wide release for unknown reasons. Official availability was announced through the company's website.

With Siri Eyes Free, owners of Sync-equipped cars are able to use in-car microphones and speakers to interact with Siri on a connected iPhone. In Ford's setup, a dedicated handsfree button mounted on the steering wheel serves the same function as the home button on an iPhone — drivers press and hold to invoke Siri. Functions available include placing phone calls, getting Apple Maps directions, sending and receiving text messages, setting reminders and alarms, playing music, looking up information about points of interest and more.

"Sync, Ford's entertainment and communications system, was designed to be flexible and updatable, just like other mobile technologies, so our customers are able to get the most out of their smartphones while behind the wheel," said Sherif Marakby, director of Ford Electronics and Electrical Systems Engineering. "Siri Eyes-Free is another great voice-activated feature that not only adds convenience but helps our customers keep their eyes on the road and hands on the wheel."

Sync version 3.8 is available for vehicles with second-generation Sync hardware, also known as MyFord Touch in North America. Owners of 2011 through 2016 model year cars can visit the MyFord website to register and receive more information. When the company first debuted the 3.8 update it said installation could take up to 30 minutes to complete.