Samsung has recently started rolling out Marshmallow update for Galaxy S6 and S6 edge. The final version has been released after an initial Beta testing where users have signed in to participate to get the beta build.If we look at it leaked screenshots, there has been minor changes in the UI. The alterations include updated notification menu, along with the regular under the hood modifications, including use of fingerprint scanner for third party applications.

Samsung has started rolling out Marshmallow update for Galaxy S6 and S6 edge in South Korea

It has also been rumored that this update will eventually get global after releasing in South Korean market.