diff --git a/pkgs/applications/gis/qgis/set-pyqt-package-dirs-ltr.patch b/pkgs/applications/gis/qgis/set-pyqt-package-dirs-ltr.patch
index 725c0b350e82..a1771d9f03d3 100644
--- a/pkgs/applications/gis/qgis/set-pyqt-package-dirs-ltr.patch
+++ b/pkgs/applications/gis/qgis/set-pyqt-package-dirs-ltr.patch
@@ -11,16 +11,6 @@ index b51fd0075e..87ee317e05 100644
      IF(_pyqt5_metadata)
        FILE(READ ${_pyqt5_metadata} _pyqt5_metadata_contents)
        STRING(REGEX REPLACE ".*\nVersion: ([^\n]+).*$" "\\1" PYQT5_VERSION_STR ${_pyqt5_metadata_contents})
-@@ -34,8 +34,8 @@ ELSE(EXISTS PYQT5_VERSION_STR)
-     ENDIF(_pyqt5_metadata)
- 
-     IF(PYQT5_VERSION_STR)
--      SET(PYQT5_MOD_DIR "${Python_SITEARCH}/PyQt5")
--      SET(PYQT5_SIP_DIR "${Python_SITEARCH}/PyQt5/bindings")
-+      SET(PYQT5_MOD_DIR "@pyQt5PackageDir@/PyQt5")
-+      SET(PYQT5_SIP_DIR "@pyQt5PackageDir@/PyQt5/bindings")
-       FIND_PROGRAM(__pyuic5 "pyuic5")
-       GET_FILENAME_COMPONENT(PYQT5_BIN_DIR ${__pyuic5} DIRECTORY)
  
 diff --git a/cmake/FindQsci.cmake b/cmake/FindQsci.cmake
 index 69e41c1fe9..5456c3d59b 100644
diff --git a/pkgs/applications/gis/qgis/unwrapped-ltr.nix b/pkgs/applications/gis/qgis/unwrapped-ltr.nix
index c6f126e28edd..ef8e21463fa1 100644
--- a/pkgs/applications/gis/qgis/unwrapped-ltr.nix
+++ b/pkgs/applications/gis/qgis/unwrapped-ltr.nix
@@ -82,14 +82,14 @@ let
   ];
 in
 mkDerivation rec {
-  version = "3.34.15";
+  version = "3.40.4";
   pname = "qgis-ltr-unwrapped";
 
   src = fetchFromGitHub {
     owner = "qgis";
     repo = "QGIS";
     rev = "final-${lib.replaceStrings [ "." ] [ "_" ] version}";
-    hash = "sha256-TFnlQIizI+8CZgNpwkuipSCNT3OYIaOeoz6kIGcSYL4=";
+    hash = "sha256-R2/ycRPQVKqleSt+9D/YCpBlqKgJdhLc0BvYT7qFJo8=";
   };
 
   passthru = {
@@ -160,6 +160,11 @@ mkDerivation rec {
       "-DWITH_3D=True"
       "-DWITH_PDAL=True"
       "-DENABLE_TESTS=False"
+      "-DQT_PLUGINS_DIR=${qtbase}/${qtbase.qtPluginPrefix}"
+
+      # Remove for QGIS 3.42
+      "-DCMAKE_POLICY_DEFAULT_CMP0175=OLD"
+      "-DCMAKE_POLICY_DEFAULT_CMP0177=OLD"
     ]
     ++ lib.optional (!withWebKit) "-DWITH_QTWEBKIT=OFF"
     ++ lib.optional withServer [