It's confirmed. The Verizon version of the Samsung Galaxy S5 will be receiving its Android 6.0.1 Marshmallow update sometime today. As always, the update will push out OTA in batches, so YMMV as far as when the update will hit your device.
The new update will be version number MMB29M.G900VVRU2DPD1, and it also adds WiFi calling, updated app icons, Ultra High Quality Audio (Hi-Fi Audio), and Android for Work. Sadly, it will also come with a ton of new bloatware... <sigh>.
Here's our dedicated section for further discussion of the Samsung Galaxy S5: Samsung Galaxy S5 Discussions
Source: Verizon