Earlier today, Samsung has begun rolling out the Android 6.0.1 Marshmallow update to their Galaxy S5 Neo devices. This update has already arrived in several European countries including Austria, Greece, UK, Germany as well as Netherlands. However, do keep in mind that currently only the SM-G903F variant are receiving the firmware update which will bring your firmware version up to G903FXXU1BPD4.
According to our tipster, this update will bring several new features to the device including the latest Google Now on Tap feature as well as a new Doze mode to improve the battery life of the device.
If you have yet to receive the update notification on your device, you can check on it manually by going to Settings > About device > Software updates.
Thanks Van Whye for the tip!