diff --git a/.github/workflows/spack_default_build.yaml b/.github/workflows/spack_default_build.yaml
index e4f596c2f..3fe72c371 100644
--- a/.github/workflows/spack_default_build.yaml
+++ b/.github/workflows/spack_default_build.yaml
@@ -129,8 +129,8 @@ jobs:
             packages:
               llvm:
                 externals:
-                - spec: llvm@18
-                  prefix: /usr/lib/llvm-18
+                - spec: llvm@16
+                  prefix: /usr/lib/llvm-16
           EOF
 
       - name: Configure GHCR mirror
@@ -145,6 +145,9 @@ jobs:
       - name: Spack develop gridkit
         run: spack -e . develop --path=$(pwd) gridkit@develop
 
+      - name: List working directory
+        run: ls -ltrh $(pwd)/*/*/
+
       - name: Concretize
         run: spack -e . concretize
 
diff --git a/Examples/ParameterEstimation/CMakeLists.txt b/Examples/ParameterEstimation/CMakeLists.txt
index 212dd5cc6..c7067b5ef 100644
--- a/Examples/ParameterEstimation/CMakeLists.txt
+++ b/Examples/ParameterEstimation/CMakeLists.txt
@@ -72,6 +72,5 @@ target_link_libraries(paramest
 # Fortran linker needed to link to HSL solvers
 set_property(TARGET paramest PROPERTY LINKER_LANGUAGE Fortran)
 install(TARGETS paramest RUNTIME DESTINATION bin)
-install(FILES lookup_table.dat DESTINATION bin)
 
 add_test(NAME ParameterEst COMMAND $<TARGET_FILE:paramest>)
diff --git a/README.md b/README.md
index 33f53555c..2542608a5 100644
--- a/README.md
+++ b/README.md
@@ -18,7 +18,8 @@ You should have all of the following installed before installing GridKit™
 	- [Suitesparse](https://github.com/DrTimothyAldenDavis/SuiteSparse) >= 5.x (optional)
 	- [Ipopt](https://github.com/coin-or/Ipopt) >= 3.x (optional)
     - [Enzyme](https://github.com/EnzymeAD/Enzyme) >=0.0.131 (optional)
-        - [LLVM](https://github.com/llvm/llvm-project) >= 18.x 
+        - [LLVM](https://github.com/llvm/llvm-project) >= 15.x. GridKit is
+          currently tested with LLVM 16. 
 - [CMake](https://cmake.org/) >= 3.12
 - C++ 17 compliant compiler