diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fdd25bf..3aabd60 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,14 +16,11 @@ jobs:
       fail-fast: false
       matrix:
         name: [
-          ubuntu-18.04-gcc-5,
-          ubuntu-18.04-gcc-6,
           ubuntu-18.04-gcc-7,
           ubuntu-18.04-gcc-8,
           ubuntu-18.04-gcc-9,
           ubuntu-20.04-gcc-10,
           ubuntu-20.04-gcc-11,
-          ubuntu-18.04-clang-3.8,
           ubuntu-18.04-clang-4.0,
           ubuntu-18.04-clang-5.0,
           ubuntu-18.04-clang-6.0,
@@ -33,10 +30,6 @@ jobs:
           ubuntu-20.04-clang-10,
           ubuntu-20.04-clang-11,
           ubuntu-20.04-clang-11-no-exceptions,
-          windows-2016-cl,
-          windows-2016-clang-cl,
-          windows-2016-clang,
-          windows-2016-gcc,
           windows-2019-cl,
           windows-2019-clang-cl,
           windows-2019-clang,
@@ -49,16 +42,6 @@ jobs:
         ]
 
         include:
-          - name: ubuntu-18.04-gcc-5
-            os: ubuntu-18.04
-            compiler: gcc
-            version: "5"
-
-          - name: ubuntu-18.04-gcc-6
-            os: ubuntu-18.04
-            compiler: gcc
-            version: "6"
-
           - name: ubuntu-18.04-gcc-7
             os: ubuntu-18.04
             compiler: gcc
@@ -84,11 +67,6 @@ jobs:
             compiler: gcc
             version: "11"
 
-          - name: ubuntu-18.04-clang-3.8
-            os: ubuntu-18.04
-            compiler: clang
-            version: "3.8"
-
           - name: ubuntu-18.04-clang-4.0
             os: ubuntu-18.04
             compiler: clang
@@ -135,26 +113,10 @@ jobs:
             version: "11"
             cmake_vars: "-DCMAKE_CXX_FLAGS=-fno-exceptions -DBUILD_TESTING=OFF -DBUILD_BENCHMARK=ON"
 
-          - name: windows-2016-cl
-            os: windows-2016
-            compiler: cl
-
-          - name: windows-2016-clang-cl
-            os: windows-2016
-            compiler: clang-cl
-
-          - name: windows-2016-clang
-            os: windows-2016
-            compiler: clang
-
           - name: windows-2019-cl
             os: windows-2019
             compiler: cl
 
-          - name: windows-2016-gcc
-            os: windows-2016
-            compiler: gcc
-
           - name: windows-2019-clang-cl
             os: windows-2019
             compiler: clang-cl
diff --git a/.github/workflows/documentation.yml b/.github/workflows/documentation.yml
index cddd438..e32cfeb 100644
--- a/.github/workflows/documentation.yml
+++ b/.github/workflows/documentation.yml
@@ -9,7 +9,7 @@ jobs:
   build-deploy:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2
     
     - name: dependencies
       env:
diff --git a/.github/workflows/single-include.yml b/.github/workflows/single-include.yml
index 44a5a66..a7b0a7f 100644
--- a/.github/workflows/single-include.yml
+++ b/.github/workflows/single-include.yml
@@ -6,7 +6,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2
     
     - name: update single include
       run: |
@@ -17,10 +17,6 @@ jobs:
       working-directory: ${{runner.workspace}}/inja/single_include/
       shell: bash
       run: |
-        pwd
-        ls inja
-        cat inja/inja.hpp
-        cat inja/inja_old.hpp
         diff inja/inja.hpp inja/inja_old.hpp >/dev/null
 
     - uses: actions/upload-artifact@v1
diff --git a/README.md b/README.md
index eb1f028..2076ace 100644
--- a/README.md
+++ b/README.md
@@ -384,8 +384,8 @@ Inja uses exceptions to handle ill-formed template input. However, exceptions ca
 
 Inja uses `string_view` from C++17, but includes the [polyfill](https://github.com/martinmoene/string-view-lite) from martinmoene. This way, the minimum version is C++11. Currently, the following compilers are tested:
 
-- GCC 5 - 11 (and possibly later)
-- Clang 3.8 - 11 (and possibly later)
-- Microsoft Visual C++ 2016 - 2019 (and possibly later)
+- GCC 7 - 11 (and possibly later)
+- Clang 4 - 12 (and possibly later)
+- Microsoft Visual C++ 2017 15.0 - 2022 (and possibly later)
 
-The unit tests fail to compile with GCC 4.8 but should just work fine. A complete list of supported compiler / os versions can be found in the [CI definition](https://github.com/pantor/inja/blob/master/.github/workflows/ci.yml).
+A list of supported compiler / os versions can be found in the [CI definition](https://github.com/pantor/inja/blob/master/.github/workflows/ci.yml).