Google's latest mobile operating system, the Android 6.0 Marshmallow is finally out. After offering it first on the Nexus 5X and Nexus 6P smartphones, the waiting game for devices from other manufacturers has also begun.

Samsung, who is among a handful of device makers to roll out fresh Android versions early, is expected to treat its current flagships soon after Google's new Nexus duo hit retail shelves. The South Korean giant's 2015 models include the Galaxy S6, Galaxy S6 Edge, and the recently launched Galaxy S6 Edge+.

When it comes to its phablet lineup, the company is predicted to introduce Android 6.0 to the Galaxy Note 5. Samsung is reportedly under pressure to distribute the new firmware soon as HTC has just unveiled a new mid-range smartphone called HTC One A9 which already offers the Marshmallow OS right out of the box.  

The Android 6.0 Marshmallow over-the-air update (OTA) for the Galaxy S6 is widely believed to commence later this year before eventually arriving at the Galaxy S5. As early as now, there are reports that a beta version of the said OS is already set and ready for testing.

Those speculations are reinforced by a recent list shared by renowned tech site GSM Arena showing which devices are slated to receive the much awaited Marshmallow OS upgrade. The site claims that those models "have been confirmed to get the latest version of its mobile platform."

A total of nine Samsung devices is included in GSM Arena's list. It comprises of the company's 2015 lineup; the Galaxy S6 edge+, Galaxy Note5, Galaxy S6 Edge, and the Galaxy S6. Last year's models such as the Galaxy S5, Galaxy Note 4 phablet, Galaxy Alpha, Galaxy A8, and Galaxy A7 are also present.

It is worth noting that 2013's Galaxy S4 is not included, as well as the Galaxy Note 3. This may not come as a surprise since Samsung has only recently updated them to Android 5.1.1 Lollipop.

Samsung-focused tech site SamMobile recently reported that the company is preparing to send out Android 6.0 to its customer worldwide, but it is planning to implement it region by region. Samsung will reportedly deliver the Marshmallow OTA update to its native South Korea first. It will then trickle down to the United States, the United Kingdom, South Asia (i.e. India), and other countries.