All Project Fi devices are getting the Android 5.1.1 in the next couple of days, Google has announced. There's currently only one handset that Project Fi subscribers can use, and it's none other than the Nexus 6.

According to a tweet sent out by Project Fi, a "sweeter" version of Android Lollipop is set to come to all Project Fi phones, and that the rollout will begin in just a few days.

"Good news! Android 5.1.1 - an even sweeter version of Android Lollipop - is coming to all Project Fi phones over the next few days," tweeted Project Fi.

Good news! Android 5.1.1 - an even sweeter version of Android Lollipop - is coming to all Project Fi phones over the next few days.

— Project Fi (@projectfi) July 9, 2015

The Nexus 6 is the first smartphone that will be incorporated by Google into Project Fi. Nexus 6 owners who have already joined the project may already have the 5.1.1 update on their devices.

Carriers such as T-Mobile and Verizon have already rolled out the new Android OS version to Nexus 6 phones. In a previous report by Tech Times, we mentioned that the Nexus 6 on AT&T is also receiving the much awaited OS. Other U.S. carriers such as Sprint and U.S. Cellular followed suit.

It's about time that the Nexus 6 gets the update from Google. While the upgrade doesn't seem like a major enhancement to the previous Android 5.1, it's meant to bring a slew of improvements and important bug fixes. Of course, most users would be more than willing to have the latest OS version on their handsets for better user experience.

Project Fi is Google's unique venture into the mobile carrier environment. It's not an entirely new carrier service but more of an MVNO wireless concept. Through this venture, subscribers will be asked to pay only for the service they use up. They can also customize their plan based on their individual needs. These features, along with the promise of no hidden charges, are the venture's biggest selling point. It has already received a number of invite requests from eager subscribers who want to join its Early Access Program.

Google promised to respond to the invite requests as quickly as it can and estimated that the invites should be able to reach everyone by mid-summer.

There's no information yet on just how many Nexus 6 owners have sent a request and have been responded to by Google. However, those who are already on the project will be receiving the Android 5.1.1 update in a matter of days, based on the latest announcement.

Users can also check manually if they already have the update by going to their phone settings menu. From there, they can go to "About phone" and "System updates" to check for the update.