Lenovo has started rolling out the latest Android Marshmallow update to the K4 Note units in India. The update comes after the complete roll out of Marshmallow update to the K3 Note, A7000, and Vibe P1 devices. However, we don’t have any details about the changes the update includes.
— Lenovo India (@Lenovo_in) June 1, 2016
Provided that the OTA update has just seeded, it will take some time before an update notification pops out on your device. Apparently, you can check for the update manually by heading to the appropriate tabs on your device’s Settings menu.