diff --git a/.github/actions/Miscellaneous/Setup_Compiler/action.yml b/.github/actions/Miscellaneous/Setup_Compiler/action.yml
index 2e8d63abd..9727adb98 100644
--- a/.github/actions/Miscellaneous/Setup_Compiler/action.yml
+++ b/.github/actions/Miscellaneous/Setup_Compiler/action.yml
@@ -15,13 +15,13 @@ runs:
           echo "CC=gcc-${vers}" >> $GITHUB_ENV
           echo "CXX=g++-${vers}" >> $GITHUB_ENV
         else
-          brew install llvm@15
           if [[ "$(uname -m)" == "x86_64" ]]; then
+            brew install llvm@15
             echo "CC=/usr/local/opt/llvm@15/bin/clang" >> $GITHUB_ENV
             echo "CXX=/usr/local/opt/llvm@15/bin/clang++" >> $GITHUB_ENV
           else
-            echo "CC=/opt/homebrew/opt/llvm@15/bin/clang" >> $GITHUB_ENV
-            echo "CXX=/opt/homebrew/opt/llvm@15/bin/clang++" >> $GITHUB_ENV
+            echo "CC=/opt/homebrew/opt/llvm@20/bin/clang" >> $GITHUB_ENV
+            echo "CXX=/opt/homebrew/opt/llvm@20/bin/clang++" >> $GITHUB_ENV
           fi
         fi
         echo "SDKROOT=$(xcrun --sdk macosx --show-sdk-path)" >> $GITHUB_ENV
@@ -75,3 +75,4 @@ runs:
         {
           echo "Unsupported compiler - fix YAML file"
         }
+
diff --git a/.github/workflows/deploy-pages.yml b/.github/workflows/deploy-pages.yml
index bcb076a2b..41521dd80 100644
--- a/.github/workflows/deploy-pages.yml
+++ b/.github/workflows/deploy-pages.yml
@@ -21,8 +21,8 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - name: osx15-arm-clang-repl-20-emscripten_wasm
-            os: macos-15
+          - name: osx26-arm-clang-repl-20-emscripten_wasm
+            os: macos-26
             clang-runtime: '20'
             cling: Off
             micromamba_shell_init: bash
diff --git a/.github/workflows/emscripten.yml b/.github/workflows/emscripten.yml
index 40b4ab9bd..7367940bb 100644
--- a/.github/workflows/emscripten.yml
+++ b/.github/workflows/emscripten.yml
@@ -28,8 +28,8 @@ jobs:
             llvm_enable_projects: "clang;lld"
             llvm_targets_to_build: "WebAssembly"
             emsdk_ver: "3.1.73"
-          - name: osx15-arm-clang-repl-20-emscripten
-            os: macos-15
+          - name: osx26-arm-clang-repl-20-emscripten
+            os: macos-26
             clang-runtime: '20'
             cling: Off
             llvm_enable_projects: "clang;lld"
@@ -367,8 +367,8 @@ jobs:
             cling: Off
             micromamba_shell_init: bash
             emsdk_ver: "3.1.73"
-          - name: osx15-arm-clang-repl-20-emscripten_wasm
-            os: macos-15
+          - name: osx26-arm-clang-repl-20-emscripten_wasm
+            os: macos-26
             clang-runtime: '20'
             cling: Off
             micromamba_shell_init: bash
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 8c308ca55..167b20518 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -110,8 +110,8 @@ jobs:
             llvm_enable_projects: "clang"
             llvm_targets_to_build: "host;NVPTX"
           # MacOS Arm Jobs
-          - name: osx15-arm-clang-clang-repl-20-out-of-process
-            os: macos-15
+          - name: osx26-arm-clang-clang-repl-20-out-of-process
+            os: macos-26
             compiler: clang
             clang-runtime: '20'
             cling: Off
@@ -119,32 +119,32 @@ jobs:
             llvm_enable_projects: "clang;compiler-rt"
             llvm_targets_to_build: "host"
             oop-jit: On
-          - name: osx15-arm-clang-clang-repl-20
-            os: macos-15
+          - name: osx26-arm-clang-clang-repl-20
+            os: macos-26
             compiler: clang
             clang-runtime: '20'
             cling: Off
             cppyy: Off
             llvm_enable_projects: "clang"
             llvm_targets_to_build: "host"
-          - name: osx15-arm-clang-clang-repl-19-cppyy
-            os: macos-15
+          - name: osx26-arm-clang-clang-repl-19-cppyy
+            os: macos-26
             compiler: clang
             clang-runtime: '19'
             cling: Off
             cppyy: On
             llvm_enable_projects: "clang"
             llvm_targets_to_build: "host"
-          - name: osx15-arm-clang-clang-repl-18-cppyy
-            os: macos-15
+          - name: osx26-arm-clang-clang-repl-18-cppyy
+            os: macos-26
             compiler: clang
             clang-runtime: '18'
             cling: Off
             cppyy: On
             llvm_enable_projects: "clang"
             llvm_targets_to_build: "host"
-          - name: osx15-arm-clang-clang18-cling-cppyy
-            os: macos-15
+          - name: osx26-arm-clang-clang18-cling-cppyy
+            os: macos-26
             compiler: clang
             clang-runtime: '18'
             cling: On