diff --git a/.azure-pipelines.yml b/.azure-pipelines.yml
index bf35a61860..a905ccbe1b 100644
--- a/.azure-pipelines.yml
+++ b/.azure-pipelines.yml
@@ -15,9 +15,9 @@ trigger:
   - ml/*
 
 jobs:
-  - job: 'ubuntu1604_gcc6_cxx14_cmake'
+  - job: 'ubuntu1804_gcc6_cxx14_cmake'
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
     steps:
       - template: .ci/azure-pipelines/steps-install-gcc.yml
         parameters:
@@ -34,9 +34,9 @@ jobs:
         parameters:
           cxxver: '14'
 
-  - job: 'ubuntu1604_gcc8_cxx14_cmake'
+  - job: 'ubuntu1804_gcc8_cxx14_cmake'
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
     steps:
       - template: .ci/azure-pipelines/steps-install-gcc.yml
         parameters:
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1e6c356e4a..cf385d698f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,7 +20,7 @@ jobs:
         include:
           - toolset: gcc-6
             cxxstd: "11,14,1z"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: g++-6
           - toolset: gcc-7
             cxxstd: "11,14,17"
@@ -62,17 +62,17 @@ jobs:
           - toolset: clang
             compiler: clang++-3.9
             cxxstd: "11,14"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: clang-3.9
           - toolset: clang
             compiler: clang++-4.0
             cxxstd: "11,14"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: clang-4.0
           - toolset: clang
             compiler: clang++-5.0
             cxxstd: "11,14,1z"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: clang-5.0
           - toolset: clang
             compiler: clang++-6.0