I just purchased Lightroom 6. I noticed on tutorial videos there is now access to whites and blacks in the graduated filter. Those sliders are not present in mine. I just purchased the most recent version. What am I missing? I checked for updates.
These were released in CC2015.1 as a dot release update to Creative Cloud subscribers ONLY.
The standalone package, Lightroom 6, does not receive functionality updates only bug fixes and camera/lens updates.
The features you mentioned were added after LR 6.0 came out so they are only part of the LR CC 2015 subscription.
New features in the serial-number-licensed LR series would be part of LR 7 if there is a LR 7.