diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d29b005..ef7855b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,25 +17,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - toolset: gcc-4.8
-            cxxstd: "03,11"
-            os: ubuntu-18.04
-            install: g++-4.8
-          - toolset: gcc-5
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
-            install: g++-5
-          - toolset: gcc-6
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
-            install: g++-6
-          - toolset: gcc-7
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
-          - toolset: gcc-8
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
-            install: g++-8
           - toolset: gcc-9
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-20.04
@@ -47,31 +28,6 @@ jobs:
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-20.04
             install: g++-11
-          - toolset: clang
-            compiler: clang++-3.9
-            cxxstd: "03,11,14"
-            os: ubuntu-18.04
-            install: clang-3.9
-          - toolset: clang
-            compiler: clang++-4.0
-            cxxstd: "03,11,14"
-            os: ubuntu-18.04
-            install: clang-4.0
-          - toolset: clang
-            compiler: clang++-5.0
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
-            install: clang-5.0
-          - toolset: clang
-            compiler: clang++-6.0
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
-            install: clang-6.0
-          - toolset: clang
-            compiler: clang++-7
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
-            install: clang-7
           - toolset: clang
             compiler: clang++-8
             cxxstd: "03,11,14,17"
@@ -99,12 +55,15 @@ jobs:
             install: clang-12
           - toolset: clang
             cxxstd: "03,11,14,17,2a"
-            os: macos-10.15
+            os: macos-11
+          - toolset: clang
+            cxxstd: "03,11,14,17,2a"
+            os: macos-12
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Install packages
         if: matrix.install
@@ -116,6 +75,9 @@ jobs:
           LIBRARY=${GITHUB_REPOSITORY#*/}
           echo LIBRARY: $LIBRARY
           echo "LIBRARY=$LIBRARY" >> $GITHUB_ENV
+          BUILD_JOBS=$((nproc || sysctl -n hw.ncpu) 2> /dev/null)
+          echo BUILD_JOBS : $BUILD_JOBS
+          echo "BUILD_JOBS=$BUILD_JOBS" >> $GITHUB_ENV
           echo GITHUB_BASE_REF: $GITHUB_BASE_REF
           echo GITHUB_REF: $GITHUB_REF
           REF=${GITHUB_BASE_REF:-$GITHUB_REF}
@@ -140,7 +102,7 @@ jobs:
       - name: Run tests
         run: |
           cd ../boost-root
-          ./b2 -j2 libs/$LIBRARY/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} variant=debug,release
+          ./b2 -j $BUILD_JOBS libs/$LIBRARY/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} variant=debug,release
 
   windows:
     strategy:
@@ -159,7 +121,7 @@ jobs:
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Setup Boost
         shell: cmd
@@ -187,4 +149,4 @@ jobs:
         shell: cmd
         run: |
           cd ../boost-root
-          b2 -j2 libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} variant=debug,release
+          b2 -j %NUMBER_OF_PROCESSORS% libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} variant=debug,release