In DP 4.5, sends can be mono, stereo, or surround. You can also assign up to 20 sends per track.

For stereo sends, a panner is now present. Stereo sends default to Send From Channel > Stereo, but you can also select Send From Channel > L or Send From Channel > R.

For surround sends, there is a button next to the send knob which, when clicked, opens the send's surround panner. Surround sends also default to Send From Channel > Surround, but you can select to send from individual channels if you want. Note that you must have a surround bundle created before you can select it as a send's output. To create a surround bundle, go to the Studio menu > Audio Bundles.

Also in DP 4.5, you can now set the number of sends you have per track, up to 20. You can change this by choosing Set Number of Sends from the Mixing Board's mini-menu.