diff --git a/README.md b/README.md
index 03661a2c..8bba2fdb 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,7 @@ GNS3 is perhaps packaged for your distribution:
 -   Alpine:
     <https://pkgs.alpinelinux.org/package/v3.10/community/x86_64/gns3-server>
 -   NixOS:
-    <https://search.nixos.org/packages?channel=21.11&from=0&size=50&sort=relevance&type=packages&query=gns3-server>
+    <https://search.nixos.org/packages?channel=unstable&from=0&size=50&sort=relevance&type=packages&query=gns3-server>
 
 Linux (Debian based)
 --------------------
diff --git a/gns3server/controller/node.py b/gns3server/controller/node.py
index f07b25df..fd3e625b 100644
--- a/gns3server/controller/node.py
+++ b/gns3server/controller/node.py
@@ -485,7 +485,7 @@ class Node:
 
         # None properties are not be send. Because it can mean the emulator doesn't support it
         for key in list(data.keys()):
-            if data[key] is None or data[key] is {} or key in self.CONTROLLER_ONLY_PROPERTIES:
+            if data[key] is None or data[key] == {} or key in self.CONTROLLER_ONLY_PROPERTIES:
                 del data[key]
 
         return data