diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e2f3e1d..5af7fd6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -79,26 +79,26 @@ jobs:
             install: clang-8
           - toolset: clang
             compiler: clang++-9
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "03,11,14,17"
             os: ubuntu-20.04
             install: clang-9
           - toolset: clang
             compiler: clang++-10
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "03,11,14,17"
             os: ubuntu-20.04
             install: clang-10
           - toolset: clang
             compiler: clang++-11
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "03,11,14,17"
             os: ubuntu-20.04
             install: clang-11
           - toolset: clang
             compiler: clang++-12
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "03,11,14,17"
             os: ubuntu-20.04
             install: clang-12
           - toolset: clang
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "03,11,14,17"
             os: macos-10.15
 
     runs-on: ${{matrix.os}}