diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e72c7d4d..16b45702 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -81,12 +81,12 @@ 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
           - toolset: clang
             compiler: clang++-11
@@ -97,7 +97,7 @@ jobs:
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-20.04
           - toolset: clang
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "03,11,14,17"
             os: macos-10.15
 
     runs-on: ${{matrix.os}}