diff --git a/pkgs/development/python-modules/bokeh/default.nix b/pkgs/development/python-modules/bokeh/default.nix
index 091b020efc25..9375aa22a3fe 100644
--- a/pkgs/development/python-modules/bokeh/default.nix
+++ b/pkgs/development/python-modules/bokeh/default.nix
@@ -33,7 +33,7 @@
 
 buildPythonPackage rec {
   pname = "bokeh";
-  version = "2.2.3";
+  version = "2.2.3";  # update together with panel which is not straightforward
 
   src = fetchPypi {
     inherit pname version;
diff --git a/pkgs/servers/zigbee2mqtt/default.nix b/pkgs/servers/zigbee2mqtt/default.nix
index 85465fd7d145..2a7c31a47a0f 100644
--- a/pkgs/servers/zigbee2mqtt/default.nix
+++ b/pkgs/servers/zigbee2mqtt/default.nix
@@ -3,6 +3,8 @@ let
   package = (import ./node.nix { inherit pkgs system; }).package;
 in
 package.override rec {
+  # don't upgrade! Newer versions cause stack overflows and fail trunk-combined
+  # see https://github.com/NixOS/nixpkgs/pull/118400
   version = "1.16.2";
   reconstructLock = true;