Samsung hasn't set a release date for the Android 6.0 Marshmallow update, but the company is obviously working on it. This weekend, Samsung accidentally sent a beta build of the Android 6.0.1 Marshmallow firmware, intended for testing on unlocked Samsung Galaxy S6 and Galaxy S6 edge devices, to a Galaxy S5.

The Galaxy S5 is slated to get the Android 6.0 Marshmallow update eventually, but of course only after the company's 2015 flagships, the Samsung Galaxy S6, Galaxy S6 edge, and Galaxy S6 edge plus, get the rollout. But according to the Samsung-centric news blog SamMobile, one lucky Samsung Galaxy S5 owner in France has received a beta build of the latest Android M build, the Android 6.0.1 Marshmallow update.

Originally reported by French tech site Frandroid, the user received what amounts to an extremely limited and personal rollout of the Android 6.0.1. Marshmallow firmware: His SM-G900F Samsung Galaxy S5 got the Android M patch from an over-the-air (OTA) update, and took screenshots to prove it.

Despite being in beta testing, and supposedly only for unlocked Galaxy S6 / Edge devices, the firmware appears to work on the Galaxy S5. Here are the details of the beta build accidentally sent to the single French Galaxy S5 from the device's "about phone" pane (translated to English).

Android Version: 6.0.1

Security Patch Date: 1 January 2016

Baseband Version: G900FXXU1CPAS        

Kernel Version: 3.4.0-6953519

Version Number: MM829M. G900FXXU1CPAS

According to the info pane, the patch was loaded last week on Monday, Jan. 18. This apparently isn't the first time Samsung has accidentally leaked its Android 6.0 Marshmallow beta build. SamMobile noted the company's Android M beta firmware made its way by mistake to a Hungarian Samsung Galaxy Note 4 about two months ago.

And as Latin Post previously reported, leaked screenshots from other Samsung users' beta builds of Android M have provided evidence that Samsung is working on an iOS-style redesign of its TouchWiz UI layer.

There's still no official word from Samsung regarding its update release date schedule; perhaps the company is planning on releasing the Android M upgrade OTA, on an individual device-by-device basis this year.