diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0ea2fde..b044f6b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -42,6 +42,7 @@ 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
@@ -87,6 +88,7 @@ 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"
@@ -96,6 +98,7 @@ 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"
@@ -104,6 +107,10 @@ 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