diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildhdf5/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildhdf5/action.yml
index 4ba086823b..b720886359 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildhdf5/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildhdf5/action.yml
@@ -34,7 +34,7 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         repository: HDFGroup/hdf5
         path: hdf5-src
@@ -50,7 +50,10 @@ runs:
         -DHDF5_ENABLE_PARALLEL=${{ inputs.enable_parallel }} \
         -DHDF5_ENABLE_Z_LIB_SUPPORT=ON \
         -DBUILD_TESTING=${{ inputs.enable_testing }} \
+        -DHDF5_ENABLE_DEPRICATED_SYMBOLS=OFF \
+        -DHDF5_BUILD_EXAMPLES=OFF \
         -DHDF5_BUILD_TOOLS=OFF \
+        -DCMAKE_BUILD_TYPE=REL \
         ../
         make
         make install
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildmpich/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildmpich/action.yml
index 3437a6065f..6b18b3c44e 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildmpich/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildmpich/action.yml
@@ -13,7 +13,7 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         repository: pmodels/mpich
         path: mpich-src
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdf/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdf/action.yml
index a7d168f657..709b05e5a1 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdf/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdf/action.yml
@@ -45,7 +45,7 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         repository: Unidata/netcdf-c
         path: netcdf-c-src
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdff/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdff/action.yml
index 4063a11cb7..0388a3358c 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdff/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildnetcdff/action.yml
@@ -19,7 +19,7 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         repository: Unidata/netcdf-fortran
         path: netcdf-fortran-src
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildopenmpi/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildopenmpi/action.yml
index f5f95fcf75..02cf3bf914 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildopenmpi/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildopenmpi/action.yml
@@ -13,7 +13,7 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         repository: open-mpi/ompi
         path: openmpi-src
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildpnetcdf/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildpnetcdf/action.yml
index 43f2ad8c05..24210fbf45 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildpnetcdf/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/buildpnetcdf/action.yml
@@ -2,7 +2,7 @@ description: 'Build the pnetcdf library'
 inputs:
   pnetcdf_version:
     description: 'Tag in the pnetcdf repository to use'
-    default: checkpoint.1.12.3
+    default: checkpoint.1.14.0
     required: False
     type: string
   install_prefix:
@@ -23,7 +23,7 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         repository: Parallel-NetCDF/PnetCDF
         path: pnetcdf-src
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/intelcompilers/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/intelcompilers/action.yml
index 5f7c658d66..895d7ea404 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/intelcompilers/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/intelcompilers/action.yml
@@ -2,22 +2,20 @@ description: 'Install Intel Compilers'
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: setup repo
       shell: bash
       run: |
-        wget https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
-        sudo apt-key add GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
-        rm GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
-        sudo echo "deb https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
+        #wget -O- https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
+        # download the key to system keyring
+        wget -O- https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB | gpg --dearmor | sudo tee /usr/share/keyrings/oneapi-archive-keyring.gpg > /dev/null
+        #sudo apt-key add GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
+        #rm GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
+        echo "deb [signed-by=/usr/share/keyrings/oneapi-archive-keyring.gpg] https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
         sudo apt-get update
     - name: install
       shell: bash
       run: |
-        sudo apt-get install -y intel-oneapi-common-vars
-        sudo apt-get install -y intel-oneapi-compiler-fortran
-        sudo apt-get install -y intel-oneapi-mkl
-        sudo apt-get install -y intel-oneapi-mpi
-        sudo apt-get install -y intel-oneapi-mpi-devel
+        sudo apt-get install intel-oneapi-hpc-toolkit
         source /opt/intel/oneapi/setvars.sh
-        printenv >> $GITHUB_ENV
+        source /opt/intel/oneapi/compiler/latest/env/vars.sh intel64
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_autotools/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_autotools/action.yml
index fd85ebe8af..4ef041708f 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_autotools/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_autotools/action.yml
@@ -2,7 +2,7 @@ description: 'Build the parallelio library using cmake'
 inputs:
   parallelio_version:
     description: 'Tag in the parallelio repository to use'
-    default: pio2_5_10
+    default: pio2_6_3
     required: False
     type: string
   shared_libraries:
@@ -101,12 +101,12 @@ runs:
   using: composite
   steps:
     - name: Check if already present
-      uses: andstor/file-existence-action@v2
+      uses: andstor/file-existence-action@v3
       with:
        files: ${{ inputs.src_path }}
     - name: get parallelio
       if: ${{ steps.check_files.outputs.files_exists != 'true' }}
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: NCAR/ParallelIO
         path: ${{ inputs.src_path }}
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_cmake/action.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_cmake/action.yml
index 5a135fce2c..c51cbe77d8 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_cmake/action.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/actions/parallelio_cmake/action.yml
@@ -2,7 +2,7 @@ description: 'Build the parallelio library using cmake'
 inputs:
   parallelio_version:
     description: 'Tag in the parallelio repository to use'
-    default: pio2_5_9
+    default: pio2_6_3
     required: False
     type: string
   shared_libraries:
@@ -110,7 +110,7 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         repository: NCAR/ParallelIO
         path: parallelio-src
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/autotools.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/autotools.yml
index eba2d60bfe..ed9cec2480 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/autotools.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/autotools.yml
@@ -19,7 +19,7 @@ jobs:
       LDFLAGS: "-L/usr/lib/x86_64-linux-gnu -lnetcdf_mpi -lpnetcdf"
       FCFLAGS: "-Wall -Werror -fallow-argument-mismatch -Wno-conversion"
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Installs
       run: |
         set -x
@@ -54,4 +54,4 @@ jobs:
 
 #    - name: Setup tmate session
 #      if: ${{ failure() }}
-#      uses: mxschmitt/action-tmate@v3
+#      uses: mxschmitt/action-tmate@v4
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake.yml
index e554dd6904..96bb68ba83 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake.yml
@@ -19,7 +19,7 @@ jobs:
 #      LDFLAGS: "-static-libasan"
 #      ASAN_OPTIONS: "detect_odr_violation=0"
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Installs
       run: |
         set -x
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake_ubuntu_latest.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake_ubuntu_latest.yml
index eb24571d5e..29beb42c49 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake_ubuntu_latest.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/cmake_ubuntu_latest.yml
@@ -23,7 +23,7 @@ jobs:
       PNETCDF_VERSION: checkpoint.1.12.3
       FCFLAGS: "-fallow-argument-mismatch"
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Installs
         run: |
           set -x
@@ -36,7 +36,7 @@ jobs:
 
       - name: cache-pnetcdf
         id: cache-pnetcdf
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/pnetcdf
           key: pnetcdf-${{ runner.os }}-${{ env.PNETCDF_VERSION }}
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/intel.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/intel.yml
deleted file mode 100644
index 10eb10fcaa..0000000000
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/intel.yml
+++ /dev/null
@@ -1,131 +0,0 @@
-name: Intel OneAPI
-# Tests ParallelIO using Intel Compiler and IMPI library.
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-jobs:
-  build:
-
-    runs-on: ubuntu-latest
-
-    env:
-      CC: mpicc
-      FC: mpiifort
-      # Versions should match the github tag names
-      PNETCDF_VERSION: checkpoint.1.12.3
-      NETCDF_C_VERSION: v4.9.2
-      NETCDF_FORTRAN_VERSION: v4.6.1
-      HDF5_VERSION: hdf5_1_12_2
-    steps:
-    - uses: actions/checkout@v3
-    - name: Installs
-      run: |
-        set -x
-        sudo apt-get update
-        sudo apt-get install libcurl4-gnutls-dev
-        sudo apt-get install libz-dev
-        echo "/opt/intel/oneapi/compiler/2023.2.1/linux/bin/intel64/" >> $GITHUB_PATH
-    - name: cache intel compiler
-      id: cache-intel
-      uses: actions/cache@v3
-      with:
-        path: /opt/intel/oneapi
-        key: intel-${{ runner.os }}
-    - name: Install Intel OneAPI
-      if: steps.cache-intel.outputs.cache-hit != 'true'
-      uses: ./.github/actions/intelcompilers
-    - name: Prep Intel OneAPI
-      if: steps.cache-intel.outputs.cache-hit == 'true'
-      run: |
-        source /opt/intel/oneapi/setvars.sh
-        printenv >> $GITHUB_ENV
-
-    - name: cache-hdf5
-      id: cache-hdf5
-      uses: actions/cache@v3
-      with:
-        path: ~/work/ParallelIO/ParallelIO/hdf5
-        key: hdf5-${{ runner.os }}-${{ env.HDF5_VERSION }}-impi
-    - name: build-hdf5
-      if: steps.cache-hdf5.outputs.cache-hit != 'true'
-      uses: ./.github/actions/buildhdf5
-      with:
-        install_prefix: ${GITHUB_WORKSPACE}/hdf5
-        enable_parallel: True
-        hdf5_version: ${{ env.HDF5_VERSION }}
-        mpi_path: /opt/intel/mpi
-    - name: cache netcdf C
-      id: cache-netcdf-c
-      uses: actions/cache@v3
-      with:
-        path: ~/work/ParallelIO/ParallelIO/netcdf-c
-        key: netcdf-c-${{ runner.os }}-${{ env.NETCDF_C_VERSION }}-impi-hdf5-${{ env.HDF5_VERSION }}
-    - name: cache netcdf Fortran
-      id: cache-netcdf-f
-      uses: actions/cache@v3
-      with:
-        path: ~/work/ParallelIO/ParallelIO/netcdf-f
-        key: netcdf-f-${{ runner.os }}-${{ env.NETCDF_FORTRAN_VERSION }}-impi-hdf5-${{ env.HDF5_VERSION }}
-
-    - name: prep netcdf-c
-      run: |
-        export PATH=$GITHUB_WORKSPACE/hdf5/bin:$GITHUB_WORKSPACE/netcdf/bin:$PATH
-        export LDFLAGS="$LDFLAGS -L$GITHUB_WORKSPACE/hdf5/lib  -L/usr/lib/x86_64-linux-gnu/ -lcurl"
-        export CPPFLAGS="$CPPFLAGS -I$GITHUB_WORKSPACE/hdf5/include -I$GITHUB_WORKSPACE/netcdf/include"
-        export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$GITHUB_WORKSPACE/hdf5/lib:/usr/lib/x86_64-linux-gnu/:/opt/intel/oneapi/compiler/2023.2.1/linux/compiler/lib/intel64_lin/"
-        printenv >> $GITHUB_ENV
-    - name: build-netcdf-c
-      if: steps.cache-netcdf-c.outputs.cache-hit != 'true'
-      uses: ./.github/actions/buildnetcdf
-      with:
-        netcdf_version: ${{ env.NETCDF_C_VERSION }}
-        install_prefix: ${GITHUB_WORKSPACE}/netcdf-c
-
-    - name: Build NetCDF Fortran
-      if: steps.cache-netcdf-f.outputs.cache-hit != 'true'
-      uses: ./.github/actions/buildnetcdff
-      with:
-        netcdf_fortran_version: ${{ env.NETCDF_FORTRAN_VERSION }}
-        install_prefix: ${GITHUB_WORKSPACE}/netcdf-f
-        netcdf_c_path: ${GITHUB_WORKSPACE}/netcdf-c
-
-    - name: cache-pnetcdf
-      id: cache-pnetcdf
-      uses: actions/cache@v3
-      with:
-        path: ~/work/ParallelIO/ParallelIO/pnetcdf
-        key: pnetcdf-${{ runner.os }}-${{ env.PNETCDF_VERSION }}-impi-5
-
-    - name: Build PNetCDF
-      if: steps.cache-pnetcdf.outputs.cache-hit != 'true'
-      uses: ./.github/actions/buildpnetcdf
-      with:
-        pnetcdf_version: ${{ env.PNETCDF_VERSION }}
-        install_prefix: ${GITHUB_WORKSPACE}/pnetcdf
-
-    - name: cmake build
-      uses: ./.github/actions/parallelio_cmake
-      with:
-        parallelio_version: ${{ env.GITHUB_SHA }}
-        enable_fortran: True
-        netcdf_c_library: $GITHUB_WORKSPACE/netcdf-c/lib/libnetcdf.so
-        netcdf_c_include_dir: $GITHUB_WORKSPACE/netcdf-c/include
-        netcdf_fortran_library: $GITHUB_WORKSPACE/netcdf-f/lib/libnetcdff.so
-        netcdf_fortran_include_dir: $GITHUB_WORKSPACE/netcdf-f/include
-        pnetcdf_library: $GITHUB_WORKSPACE/pnetcdf/lib/libpnetcdf.a
-        pnetcdf_include_dir: $GITHUB_WORKSPACE/pnetcdf/include
-        install_prefix: $GITHUB_WORKSPACE/parallelio
-    - name: parallelio tests
-      run: |
-        pushd  $GITHUB_WORKSPACE/build
-        make tests
-        ctest -VV -E test_async_
-        popd
-      #     the following can be used by developers to login to the github server in case of errors
-      #     see https://github.com/marketplace/actions/debugging-with-tmate for further details
-#    - name: Setup tmate session
-#      if: ${{ failure() }}
-#      uses: mxschmitt/action-tmate@v3
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_no_pnetcdf_ncint_mpich.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_no_pnetcdf_ncint_mpich.yml
index 81b0d0635e..44222f4456 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_no_pnetcdf_ncint_mpich.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_no_pnetcdf_ncint_mpich.yml
@@ -19,13 +19,13 @@ jobs:
       FFLAGS: "-fallow-argument-mismatch"
       FCFLAGS: "-fallow-argument-mismatch"
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Installs
       run: |
         sudo apt-get install doxygen graphviz wget gfortran libjpeg-dev libz-dev libcurl4-gnutls-dev
     - name: cache-mpich
       id: cache-mpich
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/work/ParallelIO/ParallelIO/mpich
         key: mpich-${{ runner.os }}-${{ env.MPICH_VERSION }}
@@ -39,7 +39,7 @@ jobs:
 
     - name: cache-hdf5
       id: cache-hdf5
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/work/ParallelIO/ParallelIO/hdf5
         key: hdf5-${{ runner.os }}-${{ env.HDF5_VERSION }}-mpich-${{ env.MPICH_VERSION }}
@@ -55,7 +55,7 @@ jobs:
 
     - name: cache-netcdf
       id: cache-netcdf
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/work/ParallelIO/ParallelIO/netcdf
         key: netcdf-${{ runner.os }}-${{ env.NETCDF_C_VERSION }}-${{ env.NETCDF_FORTRAN_VERSION }}-mpich-${{ env.MPICH_VERSION }}-hdf5-${{ env.HDF5_VERSION }}
@@ -79,7 +79,7 @@ jobs:
 
     - name: cache-netcdf-fortran
       id: cache-netcdf-fortran
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/netcdf-fortran
         key: netcdf-fortran-${{ runner.os }}-${{ env.NETCDF_FORTRAN_VERSION }}-mpich-${{ env.MPICH_VERSION }}-hdf5-${{ env.HDF5_VERSION }}
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_pnetcdf_ncint_mpich_asan.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_pnetcdf_ncint_mpich_asan.yml
index 5b055f0466..02c258115b 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_pnetcdf_ncint_mpich_asan.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_hdf5_pnetcdf_ncint_mpich_asan.yml
@@ -20,13 +20,13 @@ jobs:
       FCFLAGS: "-fallow-argument-mismatch"
       FFLAGS: "-fallow-argument-mismatch"
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Installs
       run: |
         sudo apt-get install doxygen graphviz wget gfortran libjpeg-dev libz-dev
     - name: cache-mpich
       id: cache-mpich
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/mpich
         key: mpich-${{ runner.os }}-${{ env.MPICH_VERSION }}
@@ -40,7 +40,7 @@ jobs:
 
     - name: cache-hdf5
       id: cache-hdf5
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/hdf5
         key: hdf5-${{ runner.os }}-${{ env.HDF5_VERSION }}-mpich-${{ env.MPICH_VERSION }}
@@ -55,7 +55,7 @@ jobs:
         mpi_path: $HOME/mpich
     - name: cache-netcdf-c
       id: cache-netcdf-c
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/netcdf-c
         key: netcdf-c-${{ runner.os }}-${{ env.NETCDF_C_VERSION }}-mpich-${{ env.MPICH_VERSION }}-hdf5-${{ env.HDF5_VERSION }}
@@ -69,7 +69,7 @@ jobs:
 
     - name: cache-netcdf-fortran
       id: cache-netcdf-fortran
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/netcdf-fortran
         key: netcdf-fortran-${{ runner.os }}-${{ env.NETCDF_F_VERSION }}-mpich-${{ env.MPICH_VERSION }}-hdf5-${{ env.HDF5_VERSION_MAJOR }}.${{ env.HDF5_VERSION_PATCH }}
@@ -84,7 +84,7 @@ jobs:
 
     - name: cache-pnetcdf
       id: cache-pnetcdf
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/pnetcdf
         key: pnetcdf-${{ runner.os }}-${{ env.PNETCDF_VERSION }}-mpich-${{ env.MPICH_VERSION }}
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_pnetcdf_openmpi.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_pnetcdf_openmpi.yml
index 1b3b6c1b05..1bd6d64d79 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_pnetcdf_openmpi.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/netcdf_pnetcdf_openmpi.yml
@@ -22,13 +22,13 @@ jobs:
       FCFLAGS: "-fallow-argument-mismatch"
       FFLAGS: "-fallow-argument-mismatch"
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Installs
       run: |
         sudo apt-get install doxygen graphviz wget gfortran libjpeg-dev libz-dev
     - name: cache-openmpi
       id: cache-openmpi
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/work/ParallelIO/ParallelIO/openmpi
         key: openmpi-${{ runner.os }}-${{ env.OPENMPI_VERSION }}
@@ -42,7 +42,7 @@ jobs:
 
     - name: cache-hdf5
       id: cache-hdf5
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/work/ParallelIO/ParallelIO/hdf5
         key: hdf5-${{ runner.os }}-${{ env.HDF5_VERSION }}-openmpi-${{ env.OPENMPI_VERSION }}
@@ -58,7 +58,7 @@ jobs:
 
     - name: cache-netcdf
       id: cache-netcdf
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/work/ParallelIO/ParallelIO/netcdf
         key: netcdf-${{ runner.os }}-${{ env.NETCDF_C_VERSION }}-${{ env.NETCDF_FORTRAN_VERSION }}-openmpi-${{ env.OPENMPI_VERSION }}-hdf5-${{ env.HDF5_VERSION }}
@@ -73,7 +73,7 @@ jobs:
 
 #    - name: Setup tmate session
 #      if: ${{ failure() }}
-#      uses: mxschmitt/action-tmate@v3
+#      uses: mxschmitt/action-tmate@v4
 
     - name: Build NetCDF Fortran
       if: steps.cache-netcdf.outputs.cache-hit != 'true'
@@ -85,7 +85,7 @@ jobs:
 
     # - name: cache-pnetcdf
     #   id: cache-pnetcdf
-    #   uses: actions/cache@v3
+    #   uses: actions/cache@v4
     #   with:
     #     path: ~/pnetcdf
     #     key: pnetcdf-${{ runner.os }}-${{ env.PNETCDF_VERSION }}-openmpi-${{ env.OPENMPI_VERSION_MAJOR }}.${{ env.OPENMPI_VERSION_PATCH }}
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/strict_autotools_ubuntu_latest.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/strict_autotools_ubuntu_latest.yml
index 952348a5fb..0fe740d542 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/strict_autotools_ubuntu_latest.yml
+++ b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/strict_autotools_ubuntu_latest.yml
@@ -20,7 +20,7 @@ jobs:
       FCFLAGS: "-fallow-argument-mismatch -Wall"
       PNETCDF_VERSION: checkpoint.1.12.3
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Installs
       run: |
         set -x
@@ -29,7 +29,7 @@ jobs:
 
     - name: cache-pnetcdf
       id: cache-pnetcdf
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/work/ParallelIO/ParallelIO/pnetcdf
         key: pnetcdf-${{ runner.os }}-${{ env.PNETCDF_VERSION }}-openmpi
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/withspack.yml b/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/withspack.yml
deleted file mode 100644
index 998d61ea01..0000000000
--- a/src/Infrastructure/IO/PIO/ParallelIO/.github/workflows/withspack.yml
+++ /dev/null
@@ -1,77 +0,0 @@
-name: Build with Spack
-# Tests ParallelIO using spack tools
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-jobs:
-  build:
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v3
-    - name: Installs
-      run: |
-        set -x
-        sudo apt-get update
-        sudo apt-get install wget
-        sudo apt-get install libjpeg-dev
-        sudo apt-get install libz-dev
-        sudo apt-get install gfortran
-
-    - name: Get latest spack release tag
-      run: |
-        export SPACK_LATEST="$(curl -sL https://github.com/spack/spack/releases/latest |grep '<title>Release' | awk '{print $2}')"
-        printenv >> $GITHUB_ENV
-    - name: cache spack
-      id: cache-spack
-      uses: actions/cache@v3
-      with:
-        path: |
-          ~/work/ParallelIO/ParallelIO/spack
-          ~/.spack
-        key: spack-${{ runner.os }}-${{ env.SPACK_LATEST }}
-    - name: Get Spack
-      if: steps.cache-spack.outputs.cache-hit != 'true'
-      uses: actions/checkout@v3
-      with:
-        repository: spack/spack
-        path: spack
-        ref: ${{ env.SPACK_LATEST }}
-
-    - name: Prep spack
-      run: |
-        source $GITHUB_WORKSPACE/spack/share/spack/setup-env.sh
-        spack compiler find
-        # Remove the patch for gfortran, we don't want it
-        #
-        sed -i 's/patch(.*$//' $GITHUB_WORKSPACE/spack/var/spack/repos/builtin/packages/parallelio/package.py
-    - name: Build with spack
-      run: |
-        source $GITHUB_WORKSPACE/spack/share/spack/setup-env.sh
-        mkdir genf90
-        pushd genf90
-        ln -fs $GITHUB_WORKSPACE/scripts/genf90.pl .
-        popd
-        # the || true prevents a fail if parallelio is not installed
-        #        spack uninstall -y parallelio@=develop+pnetcdf+fortran ^mpich || true
-        #        spack dev-build -d $GITHUB_WORKSPACE parallelio@=develop+pnetcdf+fortran ^mpich
-        spack uninstall -y parallelio@=develop+pnetcdf+fortran ^mpich || true
-        spack dev-build -d $GITHUB_WORKSPACE parallelio@=develop+pnetcdf+fortran ^mpich
-
-    - name: Test parallelio
-      run: |
-        pioblddir=$(ls -td */ | head -1)
-        pushd $pioblddir
-        make tests
-        # Exclude two tests that are timing out.
-        ctest -VV -LE skipforspack
-        popd
-
-
-    - name: Setup tmate session
-      if: ${{ failure() }}
-      uses: mxschmitt/action-tmate@v3
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/CMakeLists.txt b/src/Infrastructure/IO/PIO/ParallelIO/CMakeLists.txt
index 906727f061..7e26a0f0f6 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/CMakeLists.txt
+++ b/src/Infrastructure/IO/PIO/ParallelIO/CMakeLists.txt
@@ -10,7 +10,7 @@ project (PIO C)
 # The project version number.
 set(VERSION_MAJOR   2   CACHE STRING "Project major version number.")
 set(VERSION_MINOR   6   CACHE STRING "Project minor version number.")
-set(VERSION_PATCH   2   CACHE STRING "Project patch version number.")
+set(VERSION_PATCH   5   CACHE STRING "Project patch version number.")
 mark_as_advanced(VERSION_MAJOR VERSION_MINOR VERSION_PATCH)
 
 # Create version info in autotools parlance for pio_meta.h.
@@ -29,18 +29,18 @@ include(CheckSymbolExists)
 
 # Determine the configure date.
 IF(DEFINED ENV{SOURCE_DATE_EPOCH})
-	EXECUTE_PROCESS(
-	  COMMAND "date" "-u" "-d" "@$ENV{SOURCE_DATE_EPOCH}"
-	  OUTPUT_VARIABLE CONFIG_DATE
-	  )
+        EXECUTE_PROCESS(
+          COMMAND "date" "-u" "-d" "@$ENV{SOURCE_DATE_EPOCH}"
+          OUTPUT_VARIABLE CONFIG_DATE
+          )
 ELSE()
-	EXECUTE_PROCESS(
-	  COMMAND date
-	  OUTPUT_VARIABLE CONFIG_DATE
-	  )
+        EXECUTE_PROCESS(
+          COMMAND date
+          OUTPUT_VARIABLE CONFIG_DATE
+          )
 ENDIF()
 IF(CONFIG_DATE)
-	string(STRIP ${CONFIG_DATE} CONFIG_DATE)
+        string(STRIP ${CONFIG_DATE} CONFIG_DATE)
 ENDIF()
 
 # A function used to create autotools-style 'yes/no' definitions.
@@ -352,7 +352,7 @@ CHECK_C_SOURCE_COMPILES("
 #if !NC_HAS_SZIP_WRITE
       choke me
 #endif
-int main() {return 0;}" HAVE_SZIP_WRITE)
+int main() {return 0;}" USE_SZIP)
 
 ###
 # Check to see if parallel filters are supported by HDF5/netcdf-c.
@@ -363,9 +363,9 @@ if (HAVE_NETCDF_PAR)
 #if !NC_HAS_PAR_FILTERS
     choke me
 #endif
-int main() {return 0;}" HAVE_PAR_FILTERS)
+int main() {return 0;}" PIO_HAS_PAR_FILTERS)
 else()
-  set(HAVE_PAR_FILTERS 0)
+  set(PIO_HAS_PAR_FILTERS 0)
 endif()
 
 ###
@@ -486,7 +486,7 @@ set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
 INSTALL(FILES "${PIO_BINARY_DIR}/libpio.settings"
   DESTINATION lib
   COMPONENT libraries)
-  
+
 #####
 # Create pio_meta.h include file.
 #####
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/configure.ac b/src/Infrastructure/IO/PIO/ParallelIO/configure.ac
index 1ba2087881..7f8aa1ba28 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/configure.ac
+++ b/src/Infrastructure/IO/PIO/ParallelIO/configure.ac
@@ -2,7 +2,7 @@
 ## Ed Hartnett 8/16/17
 
 # Initialize autoconf and automake.
-AC_INIT(pio, 2.6.2)
+AC_INIT(pio, 2.6.5)
 AC_CONFIG_SRCDIR(src/clib/pio_darray.c)
 AM_INIT_AUTOMAKE([foreign serial-tests])
 
@@ -11,7 +11,7 @@ AM_INIT_AUTOMAKE([foreign serial-tests])
 # AC_DEFINE_UNQUOTED for config.h.
 AC_SUBST([PIO_VERSION_MAJOR]) PIO_VERSION_MAJOR=2
 AC_SUBST([PIO_VERSION_MINOR]) PIO_VERSION_MINOR=6
-AC_SUBST([PIO_VERSION_PATCH]) PIO_VERSION_PATCH=2
+AC_SUBST([PIO_VERSION_PATCH]) PIO_VERSION_PATCH=5
 AC_DEFINE_UNQUOTED([PIO_VERSION_MAJOR], [$PIO_VERSION_MAJOR], [PIO major version])
 AC_DEFINE_UNQUOTED([PIO_VERSION_MINOR], [$PIO_VERSION_MINOR], [PIO minor version])
 AC_DEFINE_UNQUOTED([PIO_VERSION_PATCH], [$PIO_VERSION_PATCH], [PIO patch version])
@@ -19,7 +19,7 @@ AC_DEFINE_UNQUOTED([PIO_VERSION_PATCH], [$PIO_VERSION_PATCH], [PIO patch version
 # Once more for the documentation.
 AC_SUBST([VERSION_MAJOR], [2])
 AC_SUBST([VERSION_MINOR], [6])
-AC_SUBST([VERSION_PATCH], [2])
+AC_SUBST([VERSION_PATCH], [5])
 
 
 # The m4 directory holds macros for autoconf.
@@ -38,7 +38,7 @@ fi
 LD=ld # Required for MPE to work.
 LT_INIT
 
-# Find and learn about install 
+# Find and learn about install
 AC_PROG_INSTALL
 
 # Find and learn about the C compiler.
@@ -294,7 +294,7 @@ AC_MSG_CHECKING([whether netCDF provides parallel filter support])
 AC_CHECK_LIB([netcdf], [nc_inq_filter_avail], [have_par_filters=yes], [have_par_filters=no])
 AC_MSG_RESULT([${have_par_filters}])
 if test "x$have_par_filters" = xyes ; then
-   AC_DEFINE([HAVE_PAR_FILTERS], [1], [if true, netcdf-c supports filters with parallel I/O])
+   AC_DEFINE([PIO_HAS_PAR_FILTERS], [1], [if true, netcdf-c supports filters with parallel I/O])
 fi
 
 # Is this version 4.7.2, which does not work?
@@ -472,8 +472,8 @@ AC_CONFIG_HEADERS([config.h])
 
 # Create the makefiles.
 AC_CONFIG_FILES(Makefile
-	        src/Makefile
-        	src/clib/Makefile
+                src/Makefile
+                src/clib/Makefile
                 src/ncint/Makefile
                 src/flib/Makefile
                 src/gptl/Makefile
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/doc/source/Introduction.txt b/src/Infrastructure/IO/PIO/ParallelIO/doc/source/Introduction.txt
index 888c44a84f..8393865428 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/doc/source/Introduction.txt
+++ b/src/Infrastructure/IO/PIO/ParallelIO/doc/source/Introduction.txt
@@ -45,7 +45,7 @@ processors (see @ref iosystem).
 PIO uses <a
 href=http://www.unidata.ucar.edu/software/netcdf/docs/html_guide/index.html#user_guide>
 netcdf </a> and <a
-href=http://trac.mcs.anl.gov/projects/parallel-netcdf> pnetcdf</a> to
+href=https://parallel-netcdf.github.io/> pnetcdf</a> to
 read and write the netCDF files (see @ref install).
 
 ## Basic description of how to optimize IO in a parallel environment:
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/examples/basic/kinds_mod.F90 b/src/Infrastructure/IO/PIO/ParallelIO/examples/basic/kinds_mod.F90
index ec2db1a3ae..7388264141 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/examples/basic/kinds_mod.F90
+++ b/src/Infrastructure/IO/PIO/ParallelIO/examples/basic/kinds_mod.F90
@@ -2,7 +2,7 @@
 
  module kinds_mod
 
-!BOP
+!
 ! !MODULE: kinds_mod
 !
 ! !DESCRIPTION:
@@ -31,9 +31,9 @@ module kinds_mod
       r4        = selected_real_kind(6)  ,&
       r8        = selected_real_kind(13)
 
-!EOP
-!BOC
-!EOC
+!
+!
+!
 !***********************************************************************
 
  end module kinds_mod
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/CMakeLists.txt b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/CMakeLists.txt
index 609de6f575..35e188149a 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/CMakeLists.txt
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/CMakeLists.txt
@@ -175,8 +175,8 @@ endif ()
 
 include(CheckTypeSize)
 check_type_size("size_t" SIZEOF_SIZE_T)
-CHECK_TYPE_SIZE("long long" SIZEOF_LONG_LONG)
-if (NOT ${SIZEOF_SIZE_T} EQUAL ${SIZEOF_LONG_LONG})
+check_type_size("long long" SIZEOF_LONG_LONG)
+if (NOT "${SIZEOF_SIZE_T}" STREQUAL "${SIZEOF_LONG_LONG}")
   message (FATAL_ERROR "size_t and long long must be the same size!")
 endif ()
 
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio.h b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio.h
index a4b20b7522..b15d61b0bc 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio.h
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio.h
@@ -27,6 +27,9 @@
     (((NC_VERSION_MAJOR == Maj) && (NC_VERSION_MINOR == Min) && (NC_VERSION_PATCH >= Pat)) || \
      ((NC_VERSION_MAJOR == Maj) && (NC_VERSION_MINOR > Min)) || (NC_VERSION_MAJOR > Maj))
 
+#ifndef NC_FillValue
+#define NC_FillValue _FillValue
+#endif
 
 /** PIO_OFFSET is an integer type of size sufficient to represent the
  * size (in bytes) of the largest file supported by MPI. This is not
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_darray_int.c b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_darray_int.c
index 084a214293..880ad61a0a 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_darray_int.c
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_darray_int.c
@@ -430,7 +430,7 @@ write_darray_multi_par(file_desc_t *file, int nvars, int fndims, const int *vari
 
         ierr = ncmpi_wait_all(file->fh, NC_REQ_ALL, NULL, NULL);
 #endif /* _PNETCDF */
-
+	MPI_Offset chkcnt2=0;
         /* Process each region of data to be written. */
         for (int regioncnt = 0; regioncnt < num_regions; regioncnt++)
         {
@@ -438,6 +438,11 @@ write_darray_multi_par(file_desc_t *file, int nvars, int fndims, const int *vari
             if ((ierr = find_start_count(iodesc->ndims, fndims, vdesc, region, frame,
                                          start, count)))
                 return pio_err(ios, file, ierr, __FILE__, __LINE__);
+	    size_t cnt = 1;
+	    for(int i=0; i<fndims; i++){
+		cnt *= count[i];
+	    }
+	    chkcnt2 += cnt;
 
             /* IO tasks will run the netCDF/pnetcdf functions to write the data. */
             switch (file->iotype)
@@ -490,10 +495,10 @@ write_darray_multi_par(file_desc_t *file, int nvars, int fndims, const int *vari
                     for (int i = 0; i < fndims; i++)
                     {
                         startlist[rrcnt][i] = start[i];
-                        countlist[rrcnt][i] = count[i];
-                        PLOG((3, "startlist[%d][%d] = %d countlist[%d][%d] = %d", rrcnt, i,
+                        countlist[rrcnt][i] = count[i]; 
+                        PLOG((3, "startlist[%d][%d] = %lld countlist[%d][%d] = %lld", rrcnt, i,
                               startlist[rrcnt][i], rrcnt, i, countlist[rrcnt][i]));
-                    }
+                   }
                     rrcnt++;
                 }
 
@@ -645,11 +650,22 @@ write_darray_multi_par(file_desc_t *file, int nvars, int fndims, const int *vari
                         else /* don't flush yet, accumulate the request size */
                             vard_llen += llen;
 #else
-
                         ierr = ncmpi_iput_varn(file->fh, varids[nv], rrcnt, startlist, countlist,
-                                               bufptr, llen, iodesc->mpitype, NULL);
-
-
+                                               bufptr, chkcnt2, iodesc->mpitype, NULL);
+//                                               bufptr, llen, iodesc->mpitype, NULL);
+
+
+			if (ierr){
+			    MPI_Offset chksize=0;
+			    for (int j = 0; j < rrcnt; j++)
+			    {
+/*				printf("%d: nv=%d startlist[%d][%d] = %lld countlist[%d][%d] = %lld\n", ios->io_rank, nv, j, i,
+				       startlist[j][i], j, i, countlist[j][i]);
+*/
+				chksize += countlist[j][0]*countlist[j][1]*countlist[j][2];
+			    }
+			    printf("llen = %lld chksize = %lld chkcnt2 = %lld\n",llen, chksize, chkcnt2);
+			}
                         vdesc->nreqs++;
 #endif
                     }
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc.c b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc.c
index 2808e45ec3..d6849b59ae 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc.c
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc.c
@@ -2322,7 +2322,7 @@ PIOc_def_var(int ncid, const char *name, nc_type xtype, int ndims,
  *
  * When the fill mode for the file is NC_FILL, then fill values are
  * used for missing data. This function sets the fill value to be used
- * for a variable. If no specific fill value is set (as a _FillValue
+ * for a variable. If no specific fill value is set (as a NC_FillValue
  * attribute), then the default fill values from netcdf.h are used.
  *
  * NetCDF-4 and pnetcdf files allow setting fill_mode (to NC_FILL or
@@ -2430,7 +2430,7 @@ PIOc_def_var_fill(int ncid, int varid, int fill_mode, const void *fill_valuep)
             {
                 ierr = nc_set_fill(file->fh, NC_FILL, NULL);
                 if (!ierr)
-                    ierr = nc_put_att(file->fh, varid, _FillValue, xtype, 1, fill_valuep);
+                    ierr = nc_put_att(file->fh, varid, NC_FillValue, xtype, 1, fill_valuep);
             }
         }
         else
@@ -2477,7 +2477,7 @@ PIOc_inq_var_fill(int ncid, int varid, int *no_fill, void *fill_valuep)
 {
     iosystem_desc_t *ios;  /* Pointer to io system information. */
     file_desc_t *file;     /* Pointer to file information. */
-    nc_type xtype;         /* Type of variable and its _FillValue attribute. */
+    nc_type xtype;         /* Type of variable and its NC_FillValue attribute. */
     PIO_Offset type_size;  /* Size in bytes of this variable's type. */
     int mpierr = MPI_SUCCESS, mpierr2;  /* Return code from MPI function codes. */
     int ierr = PIO_NOERR;  /* Return code from function calls. */
@@ -2574,7 +2574,7 @@ PIOc_inq_var_fill(int ncid, int varid, int *no_fill, void *fill_valuep)
 
             if (!ierr && fill_valuep)
             {
-                ierr = nc_get_att(file->fh, varid, _FillValue, fill_valuep);
+                ierr = nc_get_att(file->fh, varid, NC_FillValue, fill_valuep);
                 if (ierr == NC_ENOTATT)
                 {
                     char char_fill_value = NC_FILL_CHAR;
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc4.c b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc4.c
index 3074bbd95a..b0c045bcbe 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc4.c
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_nc4.c
@@ -1308,7 +1308,6 @@ PIOc_get_var_chunk_cache(int ncid, int varid, PIO_Offset *sizep, PIO_Offset *nel
 }
 /* use this variable in the NETCDF library (introduced in v4.9.0) to determine if the following
    functions are available */
-#ifdef NC_HAS_MULTIFILTERS
 /**
  * Set the variable filter ids
  *
@@ -1337,8 +1336,8 @@ PIOc_def_var_filter(int ncid, int varid, unsigned int id, size_t nparams, unsign
 
     PLOG((1, "PIOc_def_var_filter ncid = %d varid = %d id = %d nparams = %d", ncid, varid, id, nparams));
 #ifdef DEBUG
-    for(i=0; i<nparams; i++)
-        PLOG(1, "  param %d %d\n",i, params[i]);
+    for(int i=0; i<nparams; i++)
+        PLOG((1, "  param %d %d\n",i, params[i]));
 #endif
 
     /* Get the file info. */
@@ -1878,8 +1877,6 @@ PIOc_inq_filter_avail(int ncid, unsigned int id )
 }
 // PIO_HAS_PAR_FILTERS
 #endif 
-// NC_HAS_MULTIFILTERS
-#endif
 #ifdef NC_HAS_QUANTIZE
 /**
  * Turn on quantization for a variable
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_rearrange.c b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_rearrange.c
index 2aabacb5bd..74627f6462 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_rearrange.c
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pio_rearrange.c
@@ -80,9 +80,6 @@ expand_region(int dim, const int *gdimlen, int maplen, const PIO_Offset *map,
               int region_size, int region_stride, const int *max_size,
               PIO_Offset *count)
 {
-    /* Flag used to signal that we can no longer expand the region
-       along dimension dim. */
-    int expansion_done = 0;
     /* Check inputs. */
     pioassert(dim >= 0 && gdimlen && maplen >= 0 && map && region_size >= 0 &&
               maplen >= region_size && region_stride >= 0 && max_size && count,
@@ -100,26 +97,18 @@ expand_region(int dim, const int *gdimlen, int maplen, const PIO_Offset *map,
            Assuming monotonicity in the map, we could skip this for the
            innermost dimension, but it's necessary past that because the
            region does not necessarily comprise contiguous values. */
-        for (int j = 0; j < region_size; j++)
+	int test_idx = i * region_size;
+        for (int j = 0; j < region_size; j++, test_idx++)
         {
-            int test_idx; /* Index we are testing. */
-
-            test_idx = j + i * region_size;
-
             /* If we have exhausted the map, or the map no longer matches,
                we are done, break out of both loops. */
             //PLOG((3,"dim=%d maplen = %d map[%d]=%d map[%d]=%d i=%d region_stride=%d",dim, maplen, test_idx, map[test_idx], j, map[j],i,region_stride));
             if (test_idx >= maplen || map[test_idx] != map[j] + i * region_stride)
             {
-                expansion_done = 1;
-                break;
+		return;
             }
         }
-        if (expansion_done)
-            break;
-
     }
-    PLOG((3,"expansion_done = %d count[%d]=%ld",expansion_done, dim, count[dim]));
     /* Move on to next outermost dimension if there are more left,
      * else return. */
     if (dim > 0)
@@ -1827,7 +1816,10 @@ compare_offsets(const void *a, const void *b)
     mapsort *y = (mapsort *)b;
     if (!x || !y)
         return 0;
-    return (int)(x->iomap - y->iomap);
+
+    if (x->iomap < y->iomap) { return -1; }
+    if (x->iomap > y->iomap) { return 1; }
+    return 0;
 }
 
 /**
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pioc_support.c b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pioc_support.c
index 9d44d1ee7f..7c1c349e43 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pioc_support.c
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/clib/pioc_support.c
@@ -9,7 +9,15 @@
 #include <pio.h>
 #include <pio_internal.h>
 
+#if defined __has_include
+#if __has_include (<execinfo.h>)
+#define PLATFORM_HAS_EXECINFO
+#endif /* __has_include (<execinfo.h>) */
+#endif /* __has_include */
+
+#ifdef PLATFORM_HAS_EXECINFO
 #include <execinfo.h>
+#endif /* PLATFORM_HAS_EXECINFO */
 
 /** This is used with text decomposition files. */
 #define VERSNO 2001
@@ -522,6 +530,7 @@ pio_log(int severity, const char *fmt, ...)
 void
 print_trace(FILE *fp)
 {
+#ifdef PLATFORM_HAS_EXECINFO
     void *array[10];
     size_t size;
     char **strings;
@@ -540,6 +549,9 @@ print_trace(FILE *fp)
         fprintf(fp,"%s\n", strings[i]);
 
     free(strings);
+#else
+    (void)fp;
+#endif /* PLATFORM_HAS_EXECINFO */
 }
 
 /**
@@ -1532,6 +1544,7 @@ pioc_write_nc_decomp_int(iosystem_desc_t *ios, const char *filename, int cmode,
                                  strlen(my_order_str) + 1, my_order_str)))
         return pio_err(ios, NULL, ret, __FILE__, __LINE__);
 
+#ifdef PLATFORM_HAS_EXECINFO
     /* Write an attribute with the stack trace. This can be helpful
      * for debugging. */
     void *bt[MAX_BACKTRACE];
@@ -1562,6 +1575,7 @@ pioc_write_nc_decomp_int(iosystem_desc_t *ios, const char *filename, int cmode,
     if ((ret = PIOc_put_att_text(ncid, NC_GLOBAL, DECOMP_BACKTRACE_ATT_NAME,
                                  strlen(full_bt) + 1, full_bt)))
         return pio_err(ios, NULL, ret, __FILE__, __LINE__);
+#endif /* PLATFORM_HAS_EXECINFO */
 
     /* We need a dimension for the dimensions in the data. (Example:
      * for 4D data we will need to store 4 dimension IDs.) */
@@ -3111,7 +3125,8 @@ iotype_is_valid(int iotype)
         ret++;
 
     /* Some builds include netCDF-4. */
-#ifdef NC_HAS_NC4
+    /* as of netcdf 4.9.3 NC_HAS_NC4 is no longer defined */
+#if NC_HAS_NC4 || (NC_VERSION_PATCH > 2)
     if (iotype == PIO_IOTYPE_NETCDF4C || iotype == PIO_IOTYPE_NETCDF4P)
         ret++;
 #endif /* _NETCDF4 */
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/flib/pio_nf.F90 b/src/Infrastructure/IO/PIO/ParallelIO/src/flib/pio_nf.F90
index db08a7725b..72d6a399e3 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/flib/pio_nf.F90
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/flib/pio_nf.F90
@@ -140,7 +140,7 @@ module pio_nf
        pio_def_var_quantize                                 , &
        pio_inq_var_quantize                                 , &
 #endif
-#ifdef NC_HAS_MULTIFILTERS
+!!#ifdef NC_HAS_MULTIFILTERS
 #ifdef NC_HAS_BZ
        pio_inq_var_bzip2                                    , &
        pio_def_var_bzip2                                    , &
@@ -154,7 +154,7 @@ module pio_nf
        pio_inq_var_filter_info                              , &
        pio_inq_filter_avail                                 , &
 #endif
-#endif
+!!#endif
        pio_set_fill
   !       pio_copy_att    to be done
 
@@ -400,19 +400,19 @@ module pio_nf
 #ifdef NC_HAS_QUANTIZE
   interface pio_def_var_quantize
      module procedure &
-          def_var_quantize_desc                          , &
+          def_var_quantize_desc, &
           def_var_quantize_id
   end interface pio_def_var_quantize
   interface pio_inq_var_quantize
      module procedure &
-          inq_var_quantize_desc                          , &
+          inq_var_quantize_desc, &
           inq_var_quantize_id
   end interface pio_inq_var_quantize
 #endif
 #ifdef PIO_HAS_PAR_FILTERS
   interface pio_inq_var_filter_ids
      module procedure &
-          inq_var_filter_ids_desc                          , &
+          inq_var_filter_ids_desc , &
           inq_var_filter_ids_id
   end interface pio_inq_var_filter_ids
   interface pio_inq_var_filter_info
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/flib/piolib_mod.F90 b/src/Infrastructure/IO/PIO/ParallelIO/src/flib/piolib_mod.F90
index 908af2cfea..265a0e102d 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/flib/piolib_mod.F90
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/flib/piolib_mod.F90
@@ -1343,8 +1343,7 @@ end function pio_iotype_available
   !! @param file The returned file descriptor
   !! @param iotype @copydoc PIO_iotype
   !! @param fname The name of the file to open
-  !! @param amode_in The NetCDF creation mode flag - NC_NOWRITE for
-  !! read-only access or NC_WRITE for read-write access.
+  !! @param amode_in The NetCDF creation mode flag:  PIO_CLOBBER, PIO_NOCLOBBER, PIO_64BIT_OFFSET, PIO_64BIT_DATA
   !! @retval ierr @copydoc error_return
   !! @author Jim Edwards
   !<
diff --git a/src/Infrastructure/IO/PIO/ParallelIO/src/gptl/perf_utils.F90 b/src/Infrastructure/IO/PIO/ParallelIO/src/gptl/perf_utils.F90
index 76c7294136..88fab3c5f5 100644
--- a/src/Infrastructure/IO/PIO/ParallelIO/src/gptl/perf_utils.F90
+++ b/src/Infrastructure/IO/PIO/ParallelIO/src/gptl/perf_utils.F90
@@ -317,7 +317,7 @@ END SUBROUTINE shr_mpi_bcastl0
 
 !================== Routines from csm_share/shr/shr_file_mod.F90 ===============
 !===============================================================================
-!BOP ===========================================================================
+!===========================================================================
 !
 ! !IROUTINE: shr_file_getUnit -- Get a free FORTRAN unit number
 !
@@ -333,7 +333,7 @@ INTEGER FUNCTION shr_file_getUnit ()
 
    implicit none
 
-!EOP
+!
 
    !----- local parameters -----
    integer(SHR_KIND_IN),parameter :: shr_file_minUnit = 10      ! Min unit number to give
@@ -367,7 +367,7 @@ END FUNCTION shr_file_getUnit
 !===============================================================================
 
 !===============================================================================
-!BOP ===========================================================================
+!===============================================================================
 !
 ! !IROUTINE: shr_file_freeUnit -- Free up a FORTRAN unit number
 !
@@ -387,7 +387,7 @@ SUBROUTINE shr_file_freeUnit ( unit)
 
    integer(SHR_KIND_IN),intent(in) :: unit  ! unit number to be freed
 
-!EOP
+!
 
    !----- local parameters -----
    integer(SHR_KIND_IN),parameter :: shr_file_minUnit = 10      ! Min unit number to give