diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e2ecef8c..f1d6f3ab 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -38,6 +38,10 @@ jobs:
           - {compiler: gcc, version:  6}
           # {compiler: gcc, version:  5}
         include:
+          - {os: ubuntu-20.04, toolchain: {compiler: intel, version: '2023.2'}}
+          - {os: ubuntu-20.04, toolchain: {compiler: intel, version: '2022.2.1'}}
+          - {os: ubuntu-20.04, toolchain: {compiler: intel, version: '2021.4'}}
+
           - {os: ubuntu-22.04, toolchain: {compiler: intel, version: '2023.2'}}
           # {os: ubuntu-22.04, toolchain: {compiler: intel, version: '2023.1'}}
           # {os: ubuntu-22.04, toolchain: {compiler: intel, version: '2023.0'}}
@@ -51,6 +55,10 @@ jobs:
           # {os: ubuntu-22.04, toolchain: {compiler: intel, version: '2021.1.2'}}
           # {os: ubuntu-22.04, toolchain: {compiler: intel, version: '2021.1'}}
 
+          - {os: ubuntu-20.04, toolchain: {compiler: intel-classic, version: '2021.10'}}
+          - {os: ubuntu-20.04, toolchain: {compiler: intel-classic, version: '2021.7.1'}}
+          - {os: ubuntu-20.04, toolchain: {compiler: intel-classic, version: '2021.4'}}
+
           - {os: ubuntu-22.04, toolchain: {compiler: intel-classic, version: '2021.10'}}
           # {os: ubuntu-22.04, toolchain: {compiler: intel-classic, version: '2021.9'}}
           # {os: ubuntu-22.04, toolchain: {compiler: intel-classic, version: '2021.8'}}
diff --git a/README.md b/README.md
index 27942b59..a3321777 100644
--- a/README.md
+++ b/README.md
@@ -102,13 +102,13 @@ Supported Intel toolchains:
 
 | runner    | compiler       | version |
 | :-------- | :------------- | :------ |
-| ubuntu-\* | intel          | 2023.2, 2023.1, 2023.0, <br/> 2022.2.1, 2022.2, 2022.1, 2022.0, <br/> 2021.4, 2021.3, 2021.2, 2021.1.2, 2021.1 |
+| ubuntu-\* | intel          | 2023.2, 2023.1, 2023.0, <br/> 2022.2.1, 2022.2, 2022.1, 2022.0, <br/> 2021.4, 2021.2, 2021.1.2, 2021.1 |
 | ubuntu-\* | intel-classic  | 2021.10, 2021.9, 2021.8, <br/> 2021.7.1, 2021.7, 2021.6, 2021.5, <br/> 2021.4, 2021.3, 2021.2, 2021.1.2, 2021.1 |
 | macos-\*  | intel-classic  | 2021.10, 2021.9, 2021.8, <br/> 2021.7.1, 2021.7, 2021.6, 2021.5, <br/> 2021.4, 2021.3, 2021.2, 2021.1 |
 | windows-\* | intel | 2023.2, 2023.1, 2023.0, 2022.2.0, 2022.1.0 |
 | windows-\* | intel-classic | 2021.10.0, 2021.9.0, 2021.8.0, 2021.7.0, 2021.6.0 |
 
-**Note:** on macOS the `intel`/`ifx` compiler option is not suppoted, only `intel-classic` with the `ifort` compiler.
+**Note:** on macOS the `intel`/`ifx` compiler option is not supported, only `intel-classic` with the `ifort` compiler.
 
 ## License
 
diff --git a/action.yml b/action.yml
index b6fc225f..d7be569e 100644
--- a/action.yml
+++ b/action.yml
@@ -117,22 +117,25 @@ runs:
             echo cc=icx>>$GITHUB_OUTPUT
             echo FC=ifx>>$GITHUB_ENV
             echo CC=icx>>$GITHUB_ENV
+            echo CXX=icx>>$GITHUB_ENV
           elif [[ "${{ inputs.compiler }}" == "intel-classic" ]]; then
             echo fc=ifort>>$GITHUB_OUTPUT
             echo cc=icl>>$GITHUB_OUTPUT
             echo FC=ifort>>$GITHUB_ENV
             echo CC=icl>>$GITHUB_ENV
+            echo CXX=icl>>$GITHUB_ENV
           else
             echo fc=$FC>>$GITHUB_OUTPUT
             echo cc=$CC>>$GITHUB_OUTPUT
-            echo FC=$FC>>$GITHUB_ENV%
-            echo CC=$CC>>$GITHUB_ENV%
           fi
         else
           echo fc=$FC>>$GITHUB_OUTPUT
           echo cc=$CC>>$GITHUB_OUTPUT
-          echo FC=$FC>>$GITHUB_ENV
-          echo CC=$CC>>$GITHUB_ENV
+        fi
+
+        # intel oneapi flag to indicate env has been activated
+        if [[ "${{ inputs.compiler }}" =~ "intel" ]]; then
+          echo SETVARS_COMPLETED=1>>$GITHUB_ENV
         fi
 
     # GitHub Actions prepends GNU linker to the PATH before all bash steps, hide it so MSVC linker is found
diff --git a/setup-fortran.sh b/setup-fortran.sh
index 7f9cc151..67b5976b 100755
--- a/setup-fortran.sh
+++ b/setup-fortran.sh
@@ -131,6 +131,7 @@ CMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH
 OCL_ICD_FILENAMES=$OCL_ICD_FILENAMES
 INTEL_PYTHONHOME=$INTEL_PYTHONHOME
 CPATH=$CPATH
+SETVARS_COMPLETED=$SETVARS_COMPLETED
 EOF
   for path in ${PATH//:/ }; do
     echo $path >> $GITHUB_PATH
@@ -180,7 +181,7 @@ intel_version_map_l()
       2022.0.0 | 2022.0)
         version=2022.0.2
         ;;
-      2023.2 | 2023.1 | 2023.0 | 2022.2 | 2022.1 | 2021.4 | 2021.3 | 2021.2)
+      2023.2 | 2023.1 | 2023.0 | 2022.2 | 2022.1 | 2021.4 | 2021.2)
         version=$actual_version.0
         ;;
       2021.1)
@@ -281,7 +282,6 @@ install_intel_apt()
   $fetch https://apt.repos.intel.com/intel-gpg-keys/$_KEY > $_KEY
   sudo apt-key add $_KEY
   rm $_KEY
-  unset $_KEY
   echo "deb https://apt.repos.intel.com/oneapi all main" \
     | sudo tee /etc/apt/sources.list.d/oneAPI.list
   sudo apt-get update
@@ -427,6 +427,10 @@ install_intel_win()
   esac
 
   "$GITHUB_ACTION_PATH/install-intel-windows.bat" $WINDOWS_HPCKIT_URL
+
+  # don't call export_intel_vars here because the install may have
+  # been restored from cache. export variables in action.yml after
+  # installation or cache restore.
 }
 
 install_intel()