diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5f33e1b..29a038d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,6 +22,11 @@ jobs:
             os: ubuntu-latest
             container: ubuntu:18.04
             install: g++-4.8
+          - toolset: gcc-4.9
+            cxxstd: "03,11"
+            os: ubuntu-latest
+            container: ubuntu:16.04
+            install: g++-4.9
           - toolset: gcc-5
             cxxstd: "03,11,14,1z"
             os: ubuntu-latest