diff --git a/pkgs/applications/graphics/rawtherapee/default.nix b/pkgs/applications/graphics/rawtherapee/default.nix
index 9259b7c7648..14cbf478bd4 100644
--- a/pkgs/applications/graphics/rawtherapee/default.nix
+++ b/pkgs/applications/graphics/rawtherapee/default.nix
@@ -1,27 +1,31 @@
 { stdenv, fetchFromGitHub, pkgconfig, cmake, pixman, libpthreadstubs, gtkmm2, libXau
 , libXdmcp, lcms2, libiptcdata, libcanberra_gtk2, fftw, expat, pcre, libsigcxx
-, mercurial  # Not really needed for anything, but it fails if it does not find 'hg'
 }:
 
 stdenv.mkDerivation rec {
-  name = "rawtherapee-4.2";
+  version = "4.2.1025";
+  name = "rawtherapee-" + version;
 
   src = fetchFromGitHub {
     owner = "Beep6581";
     repo = "RawTherapee";
-    rev = "4.2";
-    sha256 = "1v4px239vlmk9l8wbzlvlyni4ns12icxmgfz21m86jkd10pj5dgr";
+    rev = "dc4bbe906ba92ddc66f98a3c26ce19822bfb99ab";
+    sha256 = "0c5za9s8533fiyl32378dq9rgd5044xi8y0wm2gkr7krbdnx74l3";
   };
 
   buildInputs = [ pkgconfig cmake pixman libpthreadstubs gtkmm2 libXau libXdmcp
-    lcms2 libiptcdata mercurial libcanberra_gtk2 fftw expat pcre libsigcxx ];
+    lcms2 libiptcdata libcanberra_gtk2 fftw expat pcre libsigcxx ];
 
-  patchPhase = ''
-    patch -p1 < ${./sigc++_fix.patch}
+  cmakeFlags = [
+    "-DPROC_TARGET_NUMBER=2"
+  ];
+
+  CMAKE_CXX_FLAGS = "-std=c++11 -Wno-deprecated-declarations -Wno-unused-result";
+
+  postUnpack = ''
+    echo "set(HG_VERSION $version)" > $sourceRoot/ReleaseInfo.cmake
   '';
 
-  NIX_CFLAGS_COMPILE = "-std=gnu++11 -Wno-deprecated-declarations -Wno-unused-result";
-
   enableParallelBuilding = true;
 
   meta = {
diff --git a/pkgs/applications/graphics/rawtherapee/sigc++_fix.patch b/pkgs/applications/graphics/rawtherapee/sigc++_fix.patch
deleted file mode 100644
index eeeefb733df..00000000000
--- a/pkgs/applications/graphics/rawtherapee/sigc++_fix.patch
+++ /dev/null
@@ -1,52 +0,0 @@
-diff --git a/rtgui/adjuster.cc b/rtgui/adjuster.cc
-index f73dd8a..a7a069c 100644
---- a/rtgui/adjuster.cc
-+++ b/rtgui/adjuster.cc
-@@ -17,7 +17,7 @@
-  *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
-  */
- #include "adjuster.h"
--#include <sigc++/class_slot.h>
-+#include <sigc++/slot.h>
- #include <cmath>
- #include "multilangmgr.h"
- #include "../rtengine/rtengine.h"
-diff --git a/rtgui/preferences.cc b/rtgui/preferences.cc
-index 134c0d7..8ce1808 100644
---- a/rtgui/preferences.cc
-+++ b/rtgui/preferences.cc
-@@ -16,7 +16,7 @@
-  *  You should have received a copy of the GNU General Public License
-  *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
-  */
--#include <sigc++/class_slot.h>
-+#include <sigc++/slot.h>
- #include "preferences.h"
- #include "multilangmgr.h"
- #include "splash.h"
-diff --git a/rtgui/thresholdadjuster.cc b/rtgui/thresholdadjuster.cc
-index 6b41329..19cde25 100644
---- a/rtgui/thresholdadjuster.cc
-+++ b/rtgui/thresholdadjuster.cc
-@@ -17,7 +17,7 @@
-  *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
-  */
- #include "thresholdadjuster.h"
--#include <sigc++/class_slot.h>
-+#include <sigc++/slot.h>
- #include <cmath>
- #include "multilangmgr.h"
- #include "../rtengine/rtengine.h"
-diff --git a/rtgui/tonecurve.cc b/rtgui/tonecurve.cc
-index 2e439e1..5f14200 100644
---- a/rtgui/tonecurve.cc
-+++ b/rtgui/tonecurve.cc
-@@ -18,7 +18,7 @@
-  */
- #include "tonecurve.h"
- #include "adjuster.h"
--#include <sigc++/class_slot.h>
-+#include <sigc++/slot.h>
- #include <iomanip>
- #include "ppversion.h"
- #include "edit.h"