So, today, the Xperia Beta Program gets expanded to include 3 new countries and to support the Xperia Z2. Registrations are open for users from Italy, Spain, and Netherlands, and in order to participate, one needs to download the Beta Program app, which is linked below this article. If you live in any of the previous 11 countries and have not joined the Beta Program last time, you will not be able to do so now – the door is only open for members of the 3 new countries.
The Xperia Blog claims that the new release is there so that the Sony UI team can iron out “any” bugs before the Android 6 update is launched to the public. So, while we wouldn't want to get anyone's hopes up in vain, it sounds like Marshmallow for eligible Xperia users is getting pretty close to launch. Back when Sony announced that it's working on a Marshmallow update, it also revealed a list of flagships and midrangers from the Xperia smartphone and tablet line, which would be eligible for the new software. See here if you are unsure whether your device is on that list.
Xperia Beta Program (Play Store link)
source: Xperia Blog