diff --git a/nix/build-all.py b/nix/build-all.py
index 0a94b68e87..1b715c555a 100644
--- a/nix/build-all.py
+++ b/nix/build-all.py
@@ -520,6 +520,7 @@ if USE_OCCT and "occ" in targets:
         download_url = "https://git.dev.opencascade.org/repos/occt.git",
         download_name = "occt",
         download_tool=download_tool_git,
+        patch="./patches/occt/enable-exception-handling.patch",
         revision="V" + OCCT_VERSION.replace('.', '_')
     )
 elif "occ" in targets:
diff --git a/nix/patches/occt/enable-exception-handling.patch b/nix/patches/occt/enable-exception-handling.patch
new file mode 100644
index 0000000000..7b9b3567fd
--- /dev/null
+++ b/nix/patches/occt/enable-exception-handling.patch
@@ -0,0 +1,17 @@
+Description: Enable exception handling
+ Upstream defaults to no exception handling for performance reasons,
+ but in OCCT's role as a shared library it's better for Debian to
+ enable it.
+Author: Kurt Kremitzki <kkremitzki@gmail.com>
+Last-Update: 2018-06-10
+
+--- a/adm/cmake/occt_defs_flags.cmake
++++ b/adm/cmake/occt_defs_flags.cmake
+@@ -138,5 +138,5 @@
+   set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -s")
+ endif()
+ 
+-set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -DNo_Exception")
+-set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -DNo_Exception")
++#set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -DNo_Exception")
++#set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -DNo_Exception")
diff --git a/win/patches/V7_3_0.patch b/win/patches/V7_3_0.patch
index c596253ec4..efc9154b75 100644
--- a/win/patches/V7_3_0.patch
+++ b/win/patches/V7_3_0.patch
@@ -13,15 +13,20 @@ index fca978164..dda41e2c6 100644
  
  # accumulate all used toolkits
 diff --git a/adm/cmake/occt_defs_flags.cmake b/adm/cmake/occt_defs_flags.cmake
-index 09da18d38..46e6e6814 100644
+index 09da18d38..a07b9cf74 100644
 --- a/adm/cmake/occt_defs_flags.cmake
 +++ b/adm/cmake/occt_defs_flags.cmake
-@@ -140,3 +140,18 @@ endif()
+@@ -138,5 +138,21 @@ if (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR MINGW)
+   set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -s")
+ endif()
  
- set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -DNo_Exception")
- set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -DNo_Exception")
-+
+-set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -DNo_Exception")
+-set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -DNo_Exception")
 +# IfcOpenShell begin
++# https://salsa.debian.org/science-team/opencascade/blob/739e7e9c4fbe575165eb3ff0251774bfad27139e/debian/patches/enable-exception-handling.patch
++# set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -DNo_Exception")
++# set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -DNo_Exception")
++
 +if (MSVC)
 +    foreach(flag CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_MINSIZEREL
 +            CMAKE_CXX_FLAGS_RELWITHDEBINFO CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE