The biggest Android device retailer may be updating a large majority of its flagships from this year and last in earliest months of 2016, if a leak of the company's purported Android Marshmallow update roadmap proves to be authentic.

An ostensible leak of Samsung's Android M update release dates for its 2015 handsets and other older Samsung devices was published by Vietnamese tech site SamsungViet. Samsung insider news blog SamMobile picked up the report this week.

If it's the genuine article, this leak exposes the Android 6.0 Marshmallow update release dates for the majority of Samsung's most popular devices, including 12 smartphones from the Korean manufacturer that can expect an OTA rollout of the Android M update as early as the first quarter of 2016.

The first devices the leak purportedly has slated for Android 6.0 Marshmallow updates in Q1 of 2016 include the following:

Samsung Galaxy Note 5

Samsung Galaxy S6

Samsung Galaxy S6 Edge

Samsung Galaxy S6 Edge Plus

Samsung Galaxy S6 Duos

Samsung Galaxy Note Edge

Samsung Galaxy Note 4

Samsung Galaxy Note 4 Duos

Samsung Galaxy S5

Samsung Galaxy S5 Neo

Samsung Galaxy S5 LTE-A

Considering how many of these devices are international or South Korean variants, those in the U.S. with one of these Samsung handsets should probably expect at least a couple weeks of lag after any OTA rollout of the Android Marshmallow update that begins in South Korea or other markets outside of the U.S.

That's because once an Android OEM like Samsung finalizes a software update, U.S. carriers must also go through testing before releasing an update over the air.

Another batch of older and less popular Samsung devices leaked in the supposed upgrade roadmap are apparently scheduled to be updated during the second quarter of next year. Here's the supposed update list for Q2 2016:

Samsung Galaxy Alpha

Samsung Galaxy Tab A

Samsung Galaxy Tab S2 8.0

Samsung Galaxy Tab S2 9.7

Of course, as this is an unconfirmed leak, take this roadmap with a grain of salt. But if it's true, Samsung owners will have something to look forward to in the new year.