HeadRush boards send only Program Change messages via their 5-Pin MIDI Out ports.
To send Program Change messages to an external MIDI device using the Prime or Core, navigate to Global Settings, tap on the MIDI tab, and enable the Send option next to Program Change.
For the Gigboard, MX5, or Pedalboard, you can configure this from the first screen in Global Settings.
Next, open your rig, go to the Hardware Assign screen, and choose a number under the MIDI Prog section. This number will be transmitted to your external MIDI device each time you select the rig.
This is useful if you're using external gear and want to change its presets in sync with rig changes on your HeadRush board.
The 5-Pin MIDI Out also serves as a Thru port, allowing any MIDI information received by the board to be passed through and sent back out to your external MIDI device.