diff --git a/lib/logitech/unifying_receiver/descriptors.py b/lib/logitech/unifying_receiver/descriptors.py
index 3d17a488..34bd02e9 100644
--- a/lib/logitech/unifying_receiver/descriptors.py
+++ b/lib/logitech/unifying_receiver/descriptors.py
@@ -47,7 +47,9 @@ def _feature_fn_swap():
 
 
 def check_features(device, already_known):
-	if _hidpp20.FEATURE.FN_INVERSION in device.features and not any(s.name == 'fn-swap' for s in already_known):
+	if device.protocol < 2.0:
+		return
+	if not any(s.name == _FN_SWAP[0] for s in already_known) and _hidpp20.FEATURE.FN_INVERSION in device.features:
 		already_known.append(_feature_fn_swap())
 
 #