Sony is edging closer to delivering the Android 6.0 Marshmallow update to its devices, as some Japanese models just got Wi-Fi Certified for the firmware.

The Wi-Fi Alliance is a Wi-Fi certification database that plays a major role in certifying devices and developing the wireless certification standard. Any new device has to go through the Wi-Fi Alliance in order to receive certification that proves it's Wi-Fi compatible, and existing devices have to go through the same process again before getting a new firmware version.

This, in turn, can offer precious indications as to when certain devices could be getting new Android updates. With that in mind, the fact that Sony Xperia Z5 and Xperia Z4 models passed through the Wi-Fi Alliance now and received Android 6.0 certification for some Japanese models indicates that the Marshmallow update could soon roll out.

Android 6.0 Marshmallow is now Wi-Fi Certified for the Sony Xperia Z5 on SoftBank, NTT docomo and au, the Xperia Z5 Premium on NTT docomo, and the Xperia Z4 on NTT docomo, SoftBank and au, the Xperia Blog reports.

Keep in mind, however, that this Wi-Fi Alliance certification is different from the PTCRB one that usually indicates that the firmware is just a couple of weeks away. It could take a bit longer for the update to roll out, but the flagship Xperia devices should nonetheless get it soon enough.

We have just reported on a rumored Marshmallow rollout for the Xperia Z5 line set for January 2016, and the latest Wi-Fi Alliance certification now seems to bolster such expectations. More devices are expected to join the party afterward, but no specific time frames are currently available.

Sony already stated its commitment to delivering the latest Android 6.0 Marshmallow update to a number of its devices in the Xperia Z family, announcing upgrade plans back in October. At the time, the company said it planned to release the update as quickly as possible, to as many devices as possible.

The company has yet to announce specific release dates for the update, but the new year should bring new treats for Sony Xperia Z flagships and it's all just around the corner.