diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 164c184..f6e73a2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -38,6 +38,7 @@ jobs:
           - 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-18.04
@@ -83,6 +84,7 @@ jobs:
             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"
@@ -92,6 +94,7 @@ jobs:
             compiler: clang++-8
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-20.04
+            install: clang-8
           - toolset: clang
             compiler: clang++-9
             cxxstd: "03,11,14,17,2a"
@@ -100,6 +103,10 @@ jobs:
             compiler: clang++-10
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-20.04
+          - toolset: clang
+            compiler: clang++-11
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-20.04
           - toolset: clang
             cxxstd: "03,11,14,17,2a"
             os: macos-10.15