I am running Lightroom 2015.6.1 and since I've updated to this version of Lightroom, I am unable to do a custom tone curve.
This is what the Tone Curve looks like on my screen:
The "Point Curve" drop down menu options are: Linear, Medium Contrast, Strong Contrast
I know there is probably a very simple solution to this, but I have not been able to figure it out yet. Any help would be greatly appreciated!
Click the little curve icon, bottom right of your screen shot. That switches it into the mode where you can edit the point curve. Is that what you meant?