[X200s] Maximum external resolution with a dock's DisplayPort

[Nickolai]

What should be the maximum resolution for a DisplayPort connection via the docking station?

I would like to be able to connect a 3440x1440 monitor like LG 34UM95.

I know the specs say 2048x1536, but they have consistently been overly conservative.

I am using a 1920x1080 monitor via DisplayPort-HDMI cable and I think I have successfully connected a 2560x1440 with DisplayPort-DisplayPort (DisplayPort-HDMI didn't let me set the full resolution).