diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 13599bc8..ed83e29a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -44,13 +44,13 @@ jobs:
       matrix:
         include:
           # Linux, gcc
-          - { compiler: gcc-4.4,   cxxstd: '98,0x',          os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: gcc-4.6,   cxxstd: '03,0x',          os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: gcc-4.7,   cxxstd: '03,11',          os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: gcc-4.8,   cxxstd: '03,11',          os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: gcc-4.9,   cxxstd: '03,11',          os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: gcc-5,     cxxstd: '03,11,14,1z',    os: ubuntu-22.04, container: 'ubuntu:18.04' }
-          - { compiler: gcc-6,     cxxstd: '03,11,14,17',    os: ubuntu-22.04, container: 'ubuntu:18.04' }
+          - { compiler: gcc-4.4,   cxxstd: '98,0x',          os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: gcc-4.6,   cxxstd: '03,0x',          os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: gcc-4.7,   cxxstd: '03,11',          os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: gcc-4.8,   cxxstd: '03,11',          os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: gcc-4.9,   cxxstd: '03,11',          os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: gcc-5,     cxxstd: '03,11,14,1z',    os: ubuntu-latest, container: 'ubuntu:18.04' }
+          - { compiler: gcc-6,     cxxstd: '03,11,14,17',    os: ubuntu-latest, container: 'ubuntu:18.04' }
           - { compiler: gcc-7,     cxxstd: '03,11,14,17',    os: ubuntu-20.04 }
           - { compiler: gcc-8,     cxxstd: '03,11,14,17,2a', os: ubuntu-20.04 }
           - { compiler: gcc-9,     cxxstd: '03,11,14,17,2a', os: ubuntu-20.04 }
@@ -63,17 +63,17 @@ jobs:
               compiler: gcc-8,     cxxstd: '03,11,14,17,2a', os: ubuntu-20.04, install: 'g++-8-multilib', address-model: '32,64' }
 
           # Linux, clang
-          - { compiler: clang-3.5, cxxstd: '03,11',          os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: clang-3.6, cxxstd: '03,11,14',       os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: clang-3.7, cxxstd: '03,11,14',       os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: clang-3.8, cxxstd: '03,11,14',       os: ubuntu-22.04, container: 'ubuntu:16.04' }
-          - { compiler: clang-3.9, cxxstd: '03,11,14',       os: ubuntu-22.04, container: 'ubuntu:18.04' }
-          - { compiler: clang-4.0, cxxstd: '03,11,14',       os: ubuntu-22.04, container: 'ubuntu:18.04' }
-          - { compiler: clang-5.0, cxxstd: '03,11,14,1z',    os: ubuntu-22.04, container: 'ubuntu:18.04' }
-          - { compiler: clang-6.0, cxxstd: '03,11,14,17',    os: ubuntu-22.04, container: 'ubuntu:18.04' }
-          - { compiler: clang-7,   cxxstd: '03,11,14,17',    os: ubuntu-22.04, container: 'ubuntu:18.04' }
+          - { compiler: clang-3.5, cxxstd: '03,11',          os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: clang-3.6, cxxstd: '03,11,14',       os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: clang-3.7, cxxstd: '03,11,14',       os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: clang-3.8, cxxstd: '03,11,14',       os: ubuntu-latest, container: 'ubuntu:16.04' }
+          - { compiler: clang-3.9, cxxstd: '03,11,14',       os: ubuntu-latest, container: 'ubuntu:18.04' }
+          - { compiler: clang-4.0, cxxstd: '03,11,14',       os: ubuntu-latest, container: 'ubuntu:18.04' }
+          - { compiler: clang-5.0, cxxstd: '03,11,14,1z',    os: ubuntu-latest, container: 'ubuntu:18.04' }
+          - { compiler: clang-6.0, cxxstd: '03,11,14,17',    os: ubuntu-latest, container: 'ubuntu:18.04' }
+          - { compiler: clang-7,   cxxstd: '03,11,14,17',    os: ubuntu-latest, container: 'ubuntu:18.04' }
           # Note: clang-8 does not fully support C++20, so it is not compatible with some libstdc++ versions in this mode
-          - { compiler: clang-8,   cxxstd: '03,11,14,17,2a', os: ubuntu-22.04, container: 'ubuntu:18.04', install: 'clang-8 g++-7', gcc_toolchain: 7 }
+          - { compiler: clang-8,   cxxstd: '03,11,14,17,2a', os: ubuntu-latest, container: 'ubuntu:18.04', install: 'clang-8 g++-7', gcc_toolchain: 7 }
           - { compiler: clang-9,   cxxstd: '03,11,14,17,2a', os: ubuntu-20.04 }
           - { compiler: clang-10,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
           - { compiler: clang-11,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
@@ -83,7 +83,7 @@ jobs:
           - { compiler: clang-14,  cxxstd: '03,11,14,17,20', os: ubuntu-22.04, install: 'clang-14 g++-12', gcc_toolchain: 12 }
 
           # libc++
-          - { compiler: clang-6.0, cxxstd: '03,11,14',       os: ubuntu-22.04, container: 'ubuntu:18.04', stdlib: libc++, install: 'clang-6.0 libc++-dev libc++abi-dev' }
+          - { compiler: clang-6.0, cxxstd: '03,11,14',       os: ubuntu-latest, container: 'ubuntu:18.04', stdlib: libc++, install: 'clang-6.0 libc++-dev libc++abi-dev' }
           - { compiler: clang-12,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev' }
           - { name: Clang w/ sanitizers, sanitize: yes,
               compiler: clang-14,  cxxstd: '03,11,14,17,20', os: ubuntu-22.04, stdlib: libc++, install: 'clang-14 libc++-14-dev libc++abi-14-dev' }
@@ -122,6 +122,7 @@ jobs:
             if [[ "${{matrix.container}}" == "ubuntu:16.04" ]] || [[ "${{matrix.container}}" == "ubuntu:18.04" ]]; then
               # Ubuntu 16/18 can't run Node 20, so stick to older actions: https://github.com/actions/checkout/issues/1590
               echo "GHA_USE_NODE_20=false" >> $GITHUB_ENV
+              echo "ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION=true" >> $GITHUB_ENV
             else
               echo "GHA_USE_NODE_20=true" >> $GITHUB_ENV
             fi