diff --git a/src/MIDI.hpp b/src/MIDI.hpp
index 084daaa..fd1f242 100644
--- a/src/MIDI.hpp
+++ b/src/MIDI.hpp
@@ -772,6 +772,7 @@ bool MidiInterface<SerialPort>::parse()
 }
 
 // Private method, see midi_Settings.h for documentation
+template<class SerialPort>
 inline void MidiInterface<SerialPort>::handleNullVelocityNoteOnAsNoteOff()
 {
     #if MIDI_HANDLE_NULL_VELOCITY_NOTE_ON_AS_NOTE_OFF