After upgrading to iOS 13 make sure Jump Desktop has access to Bluetooth devices:
On your iPad / iPhone: Open up Settings app -> Jump and make sure Bluetooth is enabled.
This article only applies to Swiftpoint or Citrix X1. If you have a generic bluetooth mouse, you'll have to enable iPad OS's AssistiveTouch feature. To do this, open up Settings app -> Accessibility -> Touch -> AssisitiveTouch and turn on AssistiveTouch. Then in the Pointer Devices section tap Devices and pair your mouse with your iPad.