Change:
<ins> { lib, callPackage, fetchgit, cmake, jq, python3Packages, qtbase, qtquickcontrols2 }: let # admittedly, we're using (printer firmware) blobs when we could compile them ourselves. curaBinaryDataVersion = "3.6.18"; # Marlin v2.0.0.144. Keep this accurate wrt. the below. curaBinaryData = fetchgit { url = https://code.alephobjects.com/diffusion/CBD/cura-binary-data.git; rev = "cdc046494bbfe1f65bfb34659a257eef9a0100a0"; sha256 = "0v0s036gxdjiglas2yzw95alv60sw3pq5k1zrrhmw9mxr4irrblb"; }; libarcusLulzbot = callPackage ./libarcus.nix { inherit (python3Packages) buildPythonPackage sip pythonOlder; }; libsavitarLulzbot = callPackage ./libsavitar.nix { inherit (python3Packages) buildPythonPackage sip pythonOlder; }; inherit (python3Packages) buildPythonPackage pyqt5 numpy scipy shapely pythonOlder; curaengine = callPackage ./curaengine.nix { inherit libarcusLulzbot; }; uraniumLulzbot = callPackage ./uranium.nix { inherit callPackage libarcusLulzbot; inherit (python3Packages) buildPythonPackage pyqt5 numpy scipy shapely pythonOlder; }; in python3Packages.buildPythonApplication rec { name = "cura-lulzbot-${version}"; version = "3.6.18"; src = fetchgit { url = https://code.alephobjects.com/source/cura-lulzbot.git; rev = "71f1ac5a2b9f535175a3858a565930348358a9ca"; sha256 = "0by06fpxvdgy858lwhsccbmvkdq67j2s1cz8v6jnrnjrsxk7vzka"; }; format = "other"; # using cmake to build buildInputs = [ qtbase qtquickcontrols2 ]; # numpy-stl temporarily disabled due to https://code.alephobjects.com/T8415 propagatedBuildInputs = with python3Packages; [ pyserial requests zeroconf ] ++ [ libsavitarLulzbot uraniumLulzbot libarcusLulzbot ]; # numpy-stl nativeBuildInputs = [ cmake python3Packages.wrapPython ]; cmakeFlags = [ "-DURANIUM_DIR=${uraniumLulzbot.src}" "-DCURA_VERSION=${version}" ]; postPatch = '' sed -i 's,/python''${PYTHON_VERSION_MAJOR}/dist-packages,/python''${PYTHON_VERSION_MAJOR}.''${PYTHON_VERSION_MINOR}/site-packages,g' CMakeLists.txt sed -i 's, executable_name = .*, executable_name = "${curaengine}/bin/CuraEngine",' plugins/CuraEngineBackend/CuraEngineBackend.py ''; preFixup = '' substituteInPlace "$out/bin/cura-lulzbot" --replace 'import cura.CuraApplication' 'import Savitar; import cura.CuraApplication' ln -sT "${curaBinaryData}/cura/resources/firmware" "$out/share/cura/resources/firmware" ln -sT "${uraniumLulzbot}/share/uranium" "$out/share/uranium" ${jq}/bin/jq --arg out "$out" '.build=$out' >"$out/version.json" <<'EOF' ${builtins.toJSON { cura = version; cura_version = version; binarydata = curaBinaryDataVersion; engine = curaengine.version; libarcus = libarcusLulzbot.version; libsavitar = libsavitarLulzbot.version; uranium = uraniumLulzbot.version; }} EOF ''; meta = with lib; { description = "3D printer / slicing GUI built on top of the Uranium framework"; homepage = https://code.alephobjects.com/diffusion/CURA/; license = licenses.agpl3;  # a partial relicense to LGPL has happened, but not certain that all AGPL bits are expunged platforms = platforms.linux; maintainers = with maintainers; [ chaduffy ]; }; } </ins>

Discussion:
Is there a way to install a more recent version of cura-lulzbot edition?
I guess the pool of people that could update and test this is very limited so feel free to tackle it yourself :) We can help. How old is the current nixpkgs version vs upstream ?
Can you test ?
Happy to, not 100% sure on the process for testing that pull request. do in build off a local version of nixpkgs with that pull applied. Can you point me in the right direction?
The one-line command to try this out would be: You could also manually clone the git repository of the PR and build it: But , so please wait a bit. EDIT: the cura binary is apparently called
you want to try the instructions gebner provided, I just updated the PR to roll the patch behind the now-broken link inline.
...FYI, the PR is now updated to 3.6.15. I'm using it happily myself, but reports (of success or failure) would be very welcome.