I have a Late 2013 15" Macbook Pro with discrete graphics.
According to this Apple support page: https://support.apple.com/en-us/HT206587 this model supports 4K 60Hz over MST.
I just purchased a Dell P2415Q monitor, which supports DisplayPort 1.2, MST, and 4K 60Hz.
I have the two connected by the included mini DisplayPort to DisplayPort cable.
And the monitor is running at 30Hz.
Everything I've read suggests that I should be able to get the monitor to run at 60Hz, but I can't find out how to. I'm trying to find answers among all the search results, but they're either outdated, different models, or asking about HDMI.
Can anyone assist me?
EDIT: Here's the monitor's display options, which show that I've turned on MST and where I'm getting that it's running at 30Hz: