Kobo Aura Hd and Mini users get the error message:

/luajit: ./frontend/ui/gesturedetector.lua:84: attempt to concatenate field 'y' (a nil value)

Hopefully the use of the "," in the DEBUG function instead of the string concatenate operator gets rid of it.

frontend/ui/gesturedetector.lua

@@ -81,7 +81,7 @@ function GestureDetector:feedEvent(tevs)
 	repeat
 		local tev = table.remove(tevs)
 		if tev then
-			DEBUG("tev fed to GestureDetector|",tev.x.."|"..tev.y.."|"..tev.id.."|"..tev.slot.."|"..tev.timev.sec.."|"..tev.timev.usec)
+			DEBUG("tev fed to GestureDetector|",tev.x,"|",tev.y,"|",tev.id,"|",tev.slot,"|",tev.timev.sec,"|",tev.timev.usec)
 			local slot = tev.slot
 			if not self.states[slot] then
 				self:clearState(slot) -- initiate state