diff --git a/.circleci/config.yml b/.circleci/config.yml
index dba98d7..fc4572a 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -101,7 +101,7 @@ jobs:
       - run:
           name: Build
           command: |
-            /tmp/cmake/build/bin/cmake -G Ninja -B build/ -DWITH_FLAKY_TESTS=Off -DCODE_COVERAGE=On -DWARNINGS_AS_ERRORS=<< parameters.warnings_as_errors >>
+            /tmp/cmake/build/bin/cmake -G Ninja -B build/ -DLLVM_REQUESTED_VERSION=15 -DWITH_FLAKY_TESTS=Off -DCODE_COVERAGE=On -DWARNINGS_AS_ERRORS=<< parameters.warnings_as_errors >>
             ninja -C build/
             # Testing rubbish:
             cp test/ci.oid.toml build/testing.oid.toml
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 071a433..254b1a9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: 16-core-ubuntu
     strategy:
       matrix:
-        llvm_version: [15]
+        llvm_version: [15, 16]
     steps:
     - uses: actions/checkout@v4.1.7
     - uses: cachix/install-nix-action@v27
diff --git a/.github/workflows/test-report.yml b/.github/workflows/test-report.yml
index 91524b1..300808b 100644
--- a/.github/workflows/test-report.yml
+++ b/.github/workflows/test-report.yml
@@ -14,7 +14,7 @@ jobs:
     steps:
     - uses: dorny/test-reporter@v1
       with:
-        artifact: test-results-15
+        artifact: test-results-16
         name: CTest Tests
         path: results.xml
         reporter: jest-junit
diff --git a/CMakeLists.txt b/CMakeLists.txt
index de8f86f..65161e5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -218,11 +218,16 @@ find_package(Boost REQUIRED COMPONENTS
 )
 message(STATUS "Linking Boost libraries: ${Boost_LIBRARIES}")
 
-### LLVM and Clang - Preferring Clang 15
-find_package(LLVM 15 REQUIRED CONFIG)
+### LLVM and Clang
+find_package(LLVM ${LLVM_REQUESTED_VERSION} REQUIRED CONFIG)
+
 message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION}")
 message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")
 
+if((${LLVM_VERSION_MAJOR} VERSION_LESS 15) OR (${LLVM_VERSION_MAJOR} VERSION_GREATER 16))
+  message(SEND_ERROR "Object Introspection currently requires an LLVM version between 15 and 16!")
+endif()
+
 find_package(Clang REQUIRED CONFIG)
 message(STATUS "Found Clang ${LLVM_PACKAGE_VERSION}")
 message(STATUS "Using ClangConfig.cmake in: ${Clang_DIR}")
diff --git a/flake.nix b/flake.nix
index f925621..39fdec3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -99,9 +99,10 @@
       in
       {
         packages = rec {
-          default = oid-llvm15;
+          default = oid-llvm16;
 
           oid-llvm15 = mkOidPackage pkgs.llvmPackages_15;
+          oid-llvm16 = mkOidPackage pkgs.llvmPackages_16;
         };
 
         apps.default = {