diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d2f32e7a1..0cbe8ad23 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,7 +8,11 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Download LLVM
-        run: sudo apt-get install llvm-11 clang-11
+        run: |
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 17
+          echo "/usr/lib/llvm-17/bin" >> $GITHUB_PATH
       - name: build odin
         run: ./build_odin.sh release
       - name: Odin version
@@ -63,10 +67,8 @@ jobs:
       - uses: actions/checkout@v1
       - name: Download LLVM, and setup PATH
         run: |
-          brew install llvm@13
-          echo "/usr/local/opt/llvm@13/bin" >> $GITHUB_PATH
-          TMP_PATH=$(xcrun --show-sdk-path)/user/include
-          echo "CPATH=$TMP_PATH" >> $GITHUB_ENV
+          brew install llvm@17
+          echo "/usr/local/opt/llvm@17/bin" >> $GITHUB_PATH
       - name: build odin
         run: ./build_odin.sh release
       - name: Odin version
@@ -104,10 +106,8 @@ jobs:
       - uses: actions/checkout@v1
       - name: Download LLVM and setup PATH
         run: |
-          brew install llvm@13
-          echo "/opt/homebrew/opt/llvm@13/bin" >> $GITHUB_PATH
-          TMP_PATH=$(xcrun --show-sdk-path)/user/include
-          echo "CPATH=$TMP_PATH" >> $GITHUB_ENV
+          brew install llvm@17
+          echo "/opt/homebrew/opt/llvm@17/bin" >> $GITHUB_PATH
       - name: build odin
         run: ./build_odin.sh release
       - name: Odin version
@@ -128,11 +128,11 @@ jobs:
       - name: Odin check examples/all
         run: ./odin check examples/all -strict-style
         timeout-minutes: 10
-      # - name: Core library tests
-      #   run: |
-      #     cd tests/core
-      #     make
-      #   timeout-minutes: 10
+      - name: Core library tests
+        run: |
+          cd tests/core
+          make
+        timeout-minutes: 10
       - name: Odin internals tests
         run: |
           cd tests/internal
diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index 709f968a7..ff90ab57e 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -47,7 +47,11 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: (Linux) Download LLVM
-        run: sudo apt-get install llvm-11 clang-11
+        run: |
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 17
+          echo "/usr/lib/llvm-17/bin" >> $GITHUB_PATH
       - name: build odin
         run: make nightly
       - name: Odin run
@@ -78,10 +82,8 @@ jobs:
       - uses: actions/checkout@v1
       - name: Download LLVM and setup PATH
         run: |
-          brew install llvm@13 dylibbundler
-          echo "/usr/local/opt/llvm@13/bin" >> $GITHUB_PATH
-          TMP_PATH=$(xcrun --show-sdk-path)/user/include
-          echo "CPATH=$TMP_PATH" >> $GITHUB_ENV
+          brew install llvm@17 dylibbundler
+          echo "/usr/local/opt/llvm@17/bin" >> $GITHUB_PATH
       - name: build odin
         # These -L makes the linker prioritize system libraries over LLVM libraries, this is mainly to
         # not link with libunwind bundled with LLVM but link with libunwind on the system.
@@ -114,10 +116,8 @@ jobs:
       - uses: actions/checkout@v1
       - name: Download LLVM and setup PATH
         run: |
-          brew install llvm@13 dylibbundler
-          echo "/opt/homebrew/opt/llvm@13/bin" >> $GITHUB_PATH
-          TMP_PATH=$(xcrun --show-sdk-path)/user/include
-          echo "CPATH=$TMP_PATH" >> $GITHUB_ENV
+          brew install llvm@17 dylibbundler
+          echo "/opt/homebrew/opt/llvm@17/bin" >> $GITHUB_PATH
       - name: build odin
         # These -L makes the linker prioritize system libraries over LLVM libraries, this is mainly to
         # not link with libunwind bundled with LLVM but link with libunwind on the system.