diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f00c388b..a9f88a23 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -33,41 +33,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - toolset: gcc-5
-            cxxstd: "03,11,14,1z"
-            address_model: 32,64
-            os: ubuntu-latest
-            container: ubuntu:16.04
-            install:
-              - g++-5-multilib
-          - toolset: gcc-5
-            cxxstd: "03-gnu,11-gnu,14-gnu,1z-gnu"
-            address_model: 32,64
-            os: ubuntu-latest
-            container: ubuntu:16.04
-            install:
-              - g++-5-multilib
-          - toolset: gcc-6
-            cxxstd: "03,11,14,1z"
-            address_model: 32,64
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - g++-6-multilib
-          - toolset: gcc-7
-            cxxstd: "03,11,14,17"
-            address_model: 32,64
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - g++-7-multilib
-          - toolset: gcc-8
-            cxxstd: "03,11,14,17,2a"
-            address_model: 32,64
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - g++-8-multilib
           - toolset: gcc-9
             cxxstd: "03,11,14,17,2a"
             address_model: 32,64
@@ -128,58 +93,6 @@ jobs:
             cxxflags: -fexcess-precision=fast
 
           # Linux, clang
-          - toolset: clang
-            compiler: clang++-3.8
-            cxxstd: "03,11,14"
-            os: ubuntu-latest
-            container: ubuntu:16.04
-            install:
-              - clang-3.8
-          - toolset: clang
-            compiler: clang++-3.9
-            cxxstd: "03,11,14"
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - clang-3.9
-          - toolset: clang
-            compiler: clang++-4.0
-            cxxstd: "03,11,14"
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - clang-4.0
-          - toolset: clang
-            compiler: clang++-5.0
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - clang-5.0
-          - toolset: clang
-            compiler: clang++-6.0
-            cxxstd: "03,11,14,17"
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - clang-6.0
-          - toolset: clang
-            compiler: clang++-7
-            cxxstd: "03,11,14,17"
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - clang-7
-          # Note: clang-8 does not fully support C++20, so it is not compatible with libstdc++-8 in this mode
-          - toolset: clang
-            compiler: clang++-8
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-latest
-            container: ubuntu:18.04
-            install:
-              - clang-8
-              - g++-7
-            gcc_toolchain: 7
           - toolset: clang
             compiler: clang++-9
             cxxstd: "03,11,14,17,2a"
@@ -334,7 +247,7 @@ jobs:
                 fi
             fi
             git config --global pack.threads 0
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install packages
         if: matrix.install
@@ -529,7 +442,7 @@ jobs:
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - name: Setup Boost
         shell: cmd
@@ -776,7 +689,7 @@ jobs:
     runs-on: ubuntu-24.04
 
     steps:
-      - uses: Jimver/cuda-toolkit@v0.2.25
+      - uses: Jimver/cuda-toolkit@v0.2.35
         id: cuda-toolkit
         with:
           cuda: '12.8.0'
@@ -788,7 +701,7 @@ jobs:
           echo "Installed cuda version is: ${{steps.cuda-toolkit.outputs.cuda}}"+
           echo "Cuda install location: ${{steps.cuda-toolkit.outputs.CUDA_PATH}}"
           nvcc -V
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Packages
         run: |
diff --git a/include/boost/charconv/detail/config.hpp b/include/boost/charconv/detail/config.hpp
index d4cba2cc..3ed01d75 100644
--- a/include/boost/charconv/detail/config.hpp
+++ b/include/boost/charconv/detail/config.hpp
@@ -197,7 +197,11 @@ static_assert((BOOST_CHARCONV_ENDIAN_BIG_BYTE || BOOST_CHARCONV_ENDIAN_LITTLE_BY
 
 #define BOOST_CHARCONV_LDBL_IS_FLOAT128
 #define BOOST_CHARCONV_UNSUPPORTED_LONG_DOUBLE
+// This identity holds only on GCC. clang keeps long double and __float128 as distinct types
+// even when both are IEEE binary128, and does not expose __float128 without -mfloat128.
+#if defined(__GNUC__) && !defined(__clang__)
 static_assert(std::is_same<long double, __float128>::value, "__float128 should be an alias to long double. Please open an issue at: https://github.com/boostorg/charconv");
+#endif
 
 #endif