diff --git a/.github/workflows/cmake-analysis.yml b/.github/workflows/cmake-analysis.yml
new file mode 100644
index 00000000000..58eb6ce584f
--- /dev/null
+++ b/.github/workflows/cmake-analysis.yml
@@ -0,0 +1,419 @@
+name: hdf5 dev ctest analysis runs
+
+# Triggers the workflow on a call from another workflow
+on:
+  workflow_call:
+    inputs:
+      snap_name:
+        description: 'The name in the source tarballs'
+        type: string
+        required: false
+        default: hdfsrc
+      file_base:
+        description: "The common base name of the source tarballs"
+        required: true
+        type: string
+      use_environ:
+        description: 'Environment to locate files'
+        type: string
+        required: true
+        default: snapshots
+
+permissions:
+  contents: read
+
+jobs:
+  coverage_test_linux_GCC:
+  # Linux (Ubuntu) w/ gcc + coverage
+  #
+    name: "Ubuntu GCC Coverage"
+    runs-on: ubuntu-latest
+    steps:
+    - name: Install CMake Dependencies (Linux_coverage)
+      run: |
+        sudo apt update
+        sudo apt-get install ninja-build doxygen graphviz curl libncurses5 build-essential
+        sudo apt install libssl3 libssl-dev libcurl4 libcurl4-openssl-dev
+        sudo apt-get install lcov -q -y
+
+    - name: Set file base name (Linux_coverage)
+      id: set-file-base
+      run: |
+        FILE_NAME_BASE=$(echo "${{ inputs.file_base }}")
+        echo "FILE_BASE=$FILE_NAME_BASE" >> $GITHUB_OUTPUT
+        if [[ '${{ inputs.use_environ }}' == 'release' ]]
+        then
+          SOURCE_NAME_BASE=$(echo "${{ inputs.snap_name }}")
+        else
+          SOURCE_NAME_BASE=$(echo "hdfsrc")
+        fi
+        echo "SOURCE_BASE=$SOURCE_NAME_BASE" >> $GITHUB_OUTPUT
+
+    # Get files created by release script
+    - name: Get tgz-tarball (Linux_coverage)
+      uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
+      with:
+        name: tgz-tarball
+        path: ${{ github.workspace }}
+
+    - name: List files for the space (Linux_coverage)
+      run: |
+        ls -l ${{ github.workspace }}
+        ls ${{ runner.workspace }}
+
+    - name: Uncompress source (Linux_coverage)
+      run: tar -zxvf ${{ github.workspace }}/${{ steps.set-file-base.outputs.FILE_BASE }}.tar.gz
+
+    - name: Copy script files for the space (Linux_coverage)
+      run: |
+        cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/CTestScript.cmake ${{ runner.workspace }}/hdf5
+        cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/HDF5config.cmake ${{ runner.workspace }}/hdf5
+
+    - name: List files for the hdf5 (Linux_coverage)
+      run: |
+        ls ${{ runner.workspace }}/hdf5
+
+    - name: Create options file (Linux_coverage)
+      uses: "DamianReeves/write-file-action@master"
+      with:
+        path: ${{ runner.workspace }}/hdf5/HDF5options.cmake
+        write-mode: overwrite
+        contents: |
+            set (CTEST_DROP_SITE_INIT "my.cdash.org")
+            # Change following line to submit to your CDash dashboard to a different CDash project
+            set (SITE_BUILDNAME_SUFFIX "${{ steps.set-file-base.outputs.FILE_BASE }}")
+            #set (CTEST_DROP_LOCATION_INIT "/submit.php?project=HDF5")
+            set (LOCAL_COVERAGE_TEST "TRUE")
+            set (LOCAL_USE_GCOV "TRUE")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_SHARED_LIBS:BOOL=OFF")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_STATIC_LIBS:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_JAVA:BOOL=OFF")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_CPP_LIB:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_FORTRAN:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_COVERAGE:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DCODE_COVERAGE:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_Z_LIB_SUPPORT:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_SUPPORT:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_ENCODING:BOOL=ON")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_PLUGIN_SUPPORT:BOOL=OFF")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DLIBAEC_USE_LOCALCONTENT:BOOL=OFF")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DZLIB_USE_LOCALCONTENT:BOOL=OFF")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_PACK_EXAMPLES:BOOL=OFF")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_PACKAGE_EXTLIBS:BOOL=OFF")
+            set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_NO_PACKAGES:BOOL=ON")
+
+    - name: Run ctest (Linux_coverage)
+      run: |
+        cd "${{ runner.workspace }}/hdf5"
+        ctest -S HDF5config.cmake,CTEST_SITE_EXT=GH_COV,LOCAL_SUBMIT=ON,NINJA=TRUE,BUILD_GENERATOR=Unix,CTEST_SOURCE_NAME=${{ steps.set-file-base.outputs.SOURCE_BASE }} -C Debug -VV -O hdf5.log
+      shell: bash
+      continue-on-error: true
+
+    # Save log files created by ctest script
+    - name: Save log (Linux_coverage)
+      uses: actions/upload-artifact@v4
+      with:
+        name: clang-coverage-log
+        path: ${{ runner.workspace }}/hdf5/hdf5.log
+        if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
+
+  build_and_test_linux_LeakSanitizer:
+  # Linux (Ubuntu) w/ clang + LeakSanitizer
+  #
+    name: "Ubuntu Clang LeakSanitizer"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install CMake Dependencies (Linux_Leak)
+        run: |
+          sudo apt update
+          sudo apt-get install ninja-build doxygen graphviz curl libncurses5
+
+      - name: add clang to env
+        uses: KyleMayes/install-llvm-action@v2.0.5
+        id: setup-clang
+        with:
+          env: true
+          version: '18'
+
+      - name: Set file base name (Linux_Leak)
+        id: set-file-base
+        run: |
+          FILE_NAME_BASE=$(echo "${{ inputs.file_base }}")
+          echo "FILE_BASE=$FILE_NAME_BASE" >> $GITHUB_OUTPUT
+          if [[ '${{ inputs.use_environ }}' == 'release' ]]
+          then
+            SOURCE_NAME_BASE=$(echo "${{ inputs.snap_name }}")
+          else
+            SOURCE_NAME_BASE=$(echo "hdfsrc")
+          fi
+          echo "SOURCE_BASE=$SOURCE_NAME_BASE" >> $GITHUB_OUTPUT
+
+      # Get files created by release script
+      - name: Get tgz-tarball (Linux_Leak)
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
+        with:
+          name: tgz-tarball
+          path: ${{ github.workspace }}
+
+      - name: List files for the space (Linux_Leak)
+        run: |
+          ls -l ${{ github.workspace }}
+          ls ${{ runner.workspace }}
+
+      - name: Uncompress source (Linux_Leak)
+        run: tar -zxvf ${{ github.workspace }}/${{ steps.set-file-base.outputs.FILE_BASE }}.tar.gz
+
+      - name: Copy script files for the space (Linux_Leak)
+        run: |
+          cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/CTestScript.cmake ${{ runner.workspace }}/hdf5
+          cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/HDF5config.cmake ${{ runner.workspace }}/hdf5
+
+      - name: List files for the hdf5 (Linux_Leak)
+        run: |
+          ls ${{ runner.workspace }}/hdf5
+
+      - name: Create options file (Linux_Leak)
+        uses: "DamianReeves/write-file-action@master"
+        with:
+          path: ${{ runner.workspace }}/hdf5/HDF5options.cmake
+          write-mode: overwrite
+          contents: |
+              set (CTEST_DROP_SITE_INIT "my.cdash.org")
+              # Change following line to submit to your CDash dashboard to a different CDash project
+              set (SITE_BUILDNAME_SUFFIX "${{ steps.set-file-base.outputs.FILE_BASE }}")
+              #set (CTEST_DROP_LOCATION_INIT "/submit.php?project=HDF5")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
+              set (MODEL "Sanitize")
+              set (GROUP "Sanitize")
+              set (LOCAL_MEMCHECK_TEST "TRUE")
+              set (CTEST_MEMORYCHECK_TYPE "LeakSanitizer")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_SHARED_LIBS:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_STATIC_LIBS:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_JAVA:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_CPP_LIB:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_FORTRAN:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SANITIZERS:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DUSE_SANITIZER:STRING=Leak")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_Z_LIB_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_ENCODING:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_PLUGIN_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DLIBAEC_USE_LOCALCONTENT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DZLIB_USE_LOCALCONTENT:BOOL=OFF")
+
+      - name: Run ctest (Linux_Leak)
+        run: |
+          cd "${{ runner.workspace }}/hdf5"
+          ctest -S HDF5config.cmake,CTEST_SITE_EXT=GH-LEAK,LOCAL_SUBMIT=ON,NINJA=TRUE,BUILD_GENERATOR=Unix,CTEST_SOURCE_NAME=${{ steps.set-file-base.outputs.SOURCE_BASE }} -C Debug -VV -O hdf5.log
+        shell: bash
+        continue-on-error: true
+
+      # Save log files created by ctest script
+      - name: Save log (Linux_Leak)
+        uses: actions/upload-artifact@v4
+        with:
+          name: leak-ubuntu-log
+          path: ${{ runner.workspace }}/hdf5/hdf5.log
+          if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
+
+  build_and_test_linux_AddressSanitizer:
+  # Linux (Ubuntu) w/ clang + AddressSanitizer
+  #
+    name: "Ubuntu Clang AddressSanitizer"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install CMake Dependencies (Linux_Address)
+        run: |
+          sudo apt update
+          sudo apt-get install ninja-build doxygen graphviz curl libncurses5
+
+      - name: add clang to env
+        uses: KyleMayes/install-llvm-action@v2.0.5
+        id: setup-clang
+        with:
+          env: true
+          version: '18'
+
+      - name: Set file base name (Linux_Address)
+        id: set-file-base
+        run: |
+          FILE_NAME_BASE=$(echo "${{ inputs.file_base }}")
+          echo "FILE_BASE=$FILE_NAME_BASE" >> $GITHUB_OUTPUT
+          if [[ '${{ inputs.use_environ }}' == 'release' ]]
+          then
+            SOURCE_NAME_BASE=$(echo "${{ inputs.snap_name }}")
+          else
+            SOURCE_NAME_BASE=$(echo "hdfsrc")
+          fi
+          echo "SOURCE_BASE=$SOURCE_NAME_BASE" >> $GITHUB_OUTPUT
+
+      # Get files created by release script
+      - name: Get tgz-tarball (Linux_Address)
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
+        with:
+          name: tgz-tarball
+          path: ${{ github.workspace }}
+
+      - name: List files for the space (Linux_Address)
+        run: |
+          ls -l ${{ github.workspace }}
+          ls ${{ runner.workspace }}
+
+      - name: Uncompress source (Linux_Address)
+        run: tar -zxvf ${{ github.workspace }}/${{ steps.set-file-base.outputs.FILE_BASE }}.tar.gz
+
+      - name: Copy script files for the space (Linux_Address)
+        run: |
+          cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/CTestScript.cmake ${{ runner.workspace }}/hdf5
+          cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/HDF5config.cmake ${{ runner.workspace }}/hdf5
+
+      - name: List files for the hdf5 (Linux_Address)
+        run: |
+          ls ${{ runner.workspace }}/hdf5
+
+      - name: Create options file (Linux_Address)
+        uses: "DamianReeves/write-file-action@master"
+        with:
+          path: ${{ runner.workspace }}/hdf5/HDF5options.cmake
+          write-mode: overwrite
+          contents: |
+              set (CTEST_DROP_SITE_INIT "my.cdash.org")
+              # Change following line to submit to your CDash dashboard to a different CDash project
+              set (SITE_BUILDNAME_SUFFIX "${{ steps.set-file-base.outputs.FILE_BASE }}")
+              #set (CTEST_DROP_LOCATION_INIT "/submit.php?project=HDF5")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
+              set (MODEL "Sanitize")
+              set (GROUP "Sanitize")
+              set (LOCAL_MEMCHECK_TEST "TRUE")
+              set (CTEST_MEMORYCHECK_TYPE "AddressSanitizer")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_SHARED_LIBS:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_STATIC_LIBS:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_JAVA:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_CPP_LIB:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_FORTRAN:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SANITIZERS:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DUSE_SANITIZER:STRING=Address")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_Z_LIB_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_ENCODING:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_PLUGIN_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DLIBAEC_USE_LOCALCONTENT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DZLIB_USE_LOCALCONTENT:BOOL=OFF")
+
+      - name: Run ctest (Linux_Address)
+        run: |
+          cd "${{ runner.workspace }}/hdf5"
+          ctest -S HDF5config.cmake,CTEST_SITE_EXT=GH-ADDR,LOCAL_SUBMIT=ON,NINJA=TRUE,BUILD_GENERATOR=Unix,CTEST_SOURCE_NAME=${{ steps.set-file-base.outputs.SOURCE_BASE }} -C Debug -VV -O hdf5.log
+        shell: bash
+        continue-on-error: true
+
+      # Save log files created by ctest script
+      - name: Save log (Linux_Address)
+        uses: actions/upload-artifact@v4
+        with:
+          name: address-ubuntu-log
+          path: ${{ runner.workspace }}/hdf5/hdf5.log
+          if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
+
+  build_and_test_linux_UndefinedBehaviorSanitizer:
+  # Linux (Ubuntu) w/ clang + UndefinedBehaviorSanitizer
+  #
+    name: "Ubuntu Clang UndefinedBehaviorSanitizer"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install CMake Dependencies (Linux_UndefinedBehavior)
+        run: |
+          sudo apt update
+          sudo apt-get install ninja-build doxygen graphviz curl libncurses5
+
+      - name: add clang to env
+        uses: KyleMayes/install-llvm-action@v2.0.5
+        id: setup-clang
+        with:
+          env: true
+          version: '18'
+
+      - name: Set file base name (Linux_UndefinedBehavior)
+        id: set-file-base
+        run: |
+          FILE_NAME_BASE=$(echo "${{ inputs.file_base }}")
+          echo "FILE_BASE=$FILE_NAME_BASE" >> $GITHUB_OUTPUT
+          if [[ '${{ inputs.use_environ }}' == 'release' ]]
+          then
+            SOURCE_NAME_BASE=$(echo "${{ inputs.snap_name }}")
+          else
+            SOURCE_NAME_BASE=$(echo "hdfsrc")
+          fi
+          echo "SOURCE_BASE=$SOURCE_NAME_BASE" >> $GITHUB_OUTPUT
+
+      # Get files created by release script
+      - name: Get tgz-tarball (Linux_UndefinedBehavior)
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
+        with:
+          name: tgz-tarball
+          path: ${{ github.workspace }}
+
+      - name: List files for the space (Linux_UndefinedBehavior)
+        run: |
+          ls -l ${{ github.workspace }}
+          ls ${{ runner.workspace }}
+
+      - name: Uncompress source (Linux_UndefinedBehavior)
+        run: tar -zxvf ${{ github.workspace }}/${{ steps.set-file-base.outputs.FILE_BASE }}.tar.gz
+
+      - name: Copy script files for the space (Linux_UndefinedBehavior)
+        run: |
+          cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/CTestScript.cmake ${{ runner.workspace }}/hdf5
+          cp ${{ github.workspace }}/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/HDF5config.cmake ${{ runner.workspace }}/hdf5
+
+      - name: List files for the hdf5 (Linux_UndefinedBehavior)
+        run: |
+          ls ${{ runner.workspace }}/hdf5
+
+      - name: Create options file (Linux_UndefinedBehavior)
+        uses: "DamianReeves/write-file-action@master"
+        with:
+          path: ${{ runner.workspace }}/hdf5/HDF5options.cmake
+          write-mode: overwrite
+          contents: |
+              set (CTEST_DROP_SITE_INIT "my.cdash.org")
+              # Change following line to submit to your CDash dashboard to a different CDash project
+              set (SITE_BUILDNAME_SUFFIX "${{ steps.set-file-base.outputs.FILE_BASE }}")
+              #set (CTEST_DROP_LOCATION_INIT "/submit.php?project=HDF5")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
+              set (MODEL "Sanitize")
+              set (GROUP "Sanitize")
+              set (LOCAL_MEMCHECK_TEST "TRUE")
+              set (CTEST_MEMORYCHECK_TYPE "UndefinedBehaviorSanitizer")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_SHARED_LIBS:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DBUILD_STATIC_LIBS:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_JAVA:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_CPP_LIB:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_FORTRAN:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SANITIZERS:BOOL=ON")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DUSE_SANITIZER:STRING=Undefined")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_Z_LIB_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_ENCODING:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_PLUGIN_SUPPORT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DLIBAEC_USE_LOCALCONTENT:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DZLIB_USE_LOCALCONTENT:BOOL=OFF")
+
+      - name: Run ctest (Linux_UndefinedBehavior)
+        run: |
+          cd "${{ runner.workspace }}/hdf5"
+          ctest -S HDF5config.cmake,CTEST_SITE_EXT=GH-UNDEF,LOCAL_SUBMIT=ON,NINJA=TRUE,BUILD_GENERATOR=Unix,CTEST_SOURCE_NAME=${{ steps.set-file-base.outputs.SOURCE_BASE }} -C Debug -VV -O hdf5.log
+        shell: bash
+        continue-on-error: true
+
+      # Save log files created by ctest script
+      - name: Save log (Linux_UndefinedBehavior)
+        uses: actions/upload-artifact@v4
+        with:
+          name: undefined-ubuntu-log
+          path: ${{ runner.workspace }}/hdf5/hdf5.log
+          if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
diff --git a/.github/workflows/cmake-script.yml b/.github/workflows/cmake-script.yml
index 35541279595..f30504f10da 100644
--- a/.github/workflows/cmake-script.yml
+++ b/.github/workflows/cmake-script.yml
@@ -490,9 +490,7 @@ jobs:
         env:
           FC: ${{ steps.setup-fortran.outputs.fc }}
           CC: ${{ steps.setup-fortran.outputs.cc }}
-          CXX: ${{ steps.setup-fortran.outputs.cxx }}
-          BINSIGN: ${{ needs.check-secret.outputs.sign-state }}
-          SIGNTOOLDIR: ${{ github.workspace }}/Microsoft.Windows.SDK.BuildTools/bin/10.0.22621.0/x64
+          CXX: ${{ steps.setup-fortran.outputs.cc }}
         run: |
           cd "${{ runner.workspace }}/hdf5"
           ctest -S HDF5config.cmake,CTEST_SITE_EXT=GH-Intel,LOCAL_SUBMIT=ON,NINJA=TRUE,BUILD_GENERATOR=VS202264,CTEST_SOURCE_NAME=${{ steps.set-file-base.outputs.SOURCE_BASE }} -C Release -VV -O hdf5.log
@@ -603,110 +601,6 @@ jobs:
           if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
 
 ####### clang builds
-  build_and_test_win_clang:
-  # Windows w/ clang + CMake
-  #
-    name: "Windows ClangCL CTest"
-    runs-on: windows-latest
-    steps:
-      - name: Install Dependencies (Windows_clang)
-        run: choco install ninja
-
-      - name: add clang to env
-        uses: KyleMayes/install-llvm-action@v2.0.5
-        id: setup-clang
-        with:
-          env: true
-          version: '18'
-
-      - name: Set file base name (Windows_clang)
-        id: set-file-base
-        run: |
-          FILE_NAME_BASE=$(echo "${{ inputs.file_base }}")
-          echo "FILE_BASE=$FILE_NAME_BASE" >> $GITHUB_OUTPUT
-          if [[ '${{ inputs.use_environ }}' == 'release' ]]
-          then
-            SOURCE_NAME_BASE=$(echo "${{ inputs.snap_name }}")
-          else
-            SOURCE_NAME_BASE=$(echo "hdfsrc")
-          fi
-          echo "SOURCE_BASE=$SOURCE_NAME_BASE" >> $GITHUB_OUTPUT
-        shell: bash
-
-      # Get files created by release script
-      - name: Get zip-tarball (Windows_clang)
-        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
-        with:
-          name: zip-tarball
-          path: ${{ github.workspace }}
-
-      - name: using powershell
-        shell: pwsh
-        run: Get-Location
-
-      - name: List files for the space (Windows_clang)
-        run: |
-          Get-ChildItem -Path ${{ github.workspace }}
-          Get-ChildItem -Path ${{ runner.workspace }}
-        shell: pwsh
-
-      - name: Uncompress source (Windows_clang)
-        working-directory: ${{ github.workspace }}
-        run: 7z x ${{ steps.set-file-base.outputs.FILE_BASE }}.zip
-        shell: bash
-
-      - name: Copy script files for the space (Windows_clang)
-        run: |
-          Copy-Item -Path ${{ runner.workspace }}/hdf5/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/CTestScript.cmake -Destination ${{ runner.workspace }}/hdf5/
-          Copy-Item -Path ${{ runner.workspace }}/hdf5/${{ steps.set-file-base.outputs.SOURCE_BASE }}/config/cmake/scripts/HDF5config.cmake -Destination ${{ runner.workspace }}/hdf5/
-        shell: pwsh
-
-      - name: List files for the hdf5 (Windows_clang)
-        run: |
-          Get-ChildItem -Path ${{ runner.workspace }}/hdf5
-        shell: pwsh
-
-      - name: Create options file (Windows_clang)
-        uses: "DamianReeves/write-file-action@master"
-        with:
-          path: ${{ runner.workspace }}/hdf5/HDF5options.cmake
-          write-mode: overwrite
-          contents: |
-              set (CTEST_DROP_SITE_INIT "my.cdash.org")
-              # Change following line to submit to your CDash dashboard to a different CDash project
-              #set (CTEST_DROP_LOCATION_INIT "/submit.php?project=HDF5")
-              set (SITE_BUILDNAME_SUFFIX "${{ steps.set-file-base.outputs.FILE_BASE }}")
-              #set (CMAKE_GENERATOR_TOOLSET "ClangCL")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} --log-level=VERBOSE")
-              #set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DCMAKE_TOOLCHAIN_FILE:STRING=config/toolchain/clang.cmake")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_JAVA:BOOL=ON")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_CPP_LIB:BOOL=ON")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_FORTRAN:BOOL=OFF")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_Z_LIB_SUPPORT:BOOL=ON")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_SUPPORT:BOOL=ON")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SZIP_ENCODING:BOOL=ON")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_PLUGIN_SUPPORT:BOOL=ON")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DLIBAEC_USE_LOCALCONTENT:BOOL=OFF")
-              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DZLIB_USE_LOCALCONTENT:BOOL=OFF")
-
-      - name: Run ctest (Windows_clang) with clang
-        env:
-          BINSIGN: ${{ needs.check-secret.outputs.sign-state }}
-          SIGNTOOLDIR: ${{ github.workspace }}/Microsoft.Windows.SDK.BuildTools/bin/10.0.22621.0/x64
-        run: |
-          cd "${{ runner.workspace }}/hdf5"
-          ctest -S HDF5config.cmake,CTEST_SITE_EXT=GH-Clang,LOCAL_SUBMIT=ON,NINJA=TRUE,BUILD_GENERATOR=VS202264,CTEST_SOURCE_NAME=${{ steps.set-file-base.outputs.SOURCE_BASE }} -C Release -VV -O hdf5.log
-        shell: pwsh
-        continue-on-error: true
-
-      # Save log files created by ctest script
-      - name: Save log (Windows_clang)
-        uses: actions/upload-artifact@v4
-        with:
-          name: clang-win-log
-          path: ${{ runner.workspace }}/hdf5/hdf5.log
-          if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
-
   build_and_test_linux_clang:
   # Linux (Ubuntu) w/ clang + CMake
   #
diff --git a/.github/workflows/daily-build.yml b/.github/workflows/daily-build.yml
index ef98e353ab2..65150c5f3ec 100644
--- a/.github/workflows/daily-build.yml
+++ b/.github/workflows/daily-build.yml
@@ -1,6 +1,7 @@
 name: hdf5 dev daily build
 
-# Triggers the workflow on a schedule or on demand
+# Triggers the workflow on demand or on a call from another workflow
+# NOTE: inputs must be duplicated between triggers
 on:
   workflow_dispatch:
     inputs:
@@ -9,8 +10,13 @@ on:
         type: string
         required: false
         default: check
-  schedule:
-    - cron: "6 0 * * *"
+  workflow_call:
+    inputs:
+      use_ignore:
+        description: 'Ignore has_changes check'
+        type: string
+        required: false
+        default: check
 
 permissions:
   contents: read
@@ -61,6 +67,14 @@ jobs:
       use_environ: snapshots
     if: ${{ ((needs.call-workflow-tarball.outputs.has_changes == 'true') || (needs.get-old-names.outputs.run-ignore == 'ignore')) }}
 
+  call-workflow-sanitizers:
+    needs: [get-old-names, call-workflow-tarball]
+    uses: ./.github/workflows/cmake-analysis.yml
+    with:
+      file_base: ${{ needs.call-workflow-tarball.outputs.file_base }}
+      use_environ: snapshots
+    if: ${{ ((needs.call-workflow-tarball.outputs.has_changes == 'true') || (needs.get-old-names.outputs.run-ignore == 'ignore')) }}
+
   call-workflow-ctest:
     needs: [get-old-names, call-workflow-tarball]
     uses: ./.github/workflows/cmake-ctest.yml
diff --git a/.github/workflows/daily-schedule.yml b/.github/workflows/daily-schedule.yml
new file mode 100644
index 00000000000..83486c97696
--- /dev/null
+++ b/.github/workflows/daily-schedule.yml
@@ -0,0 +1,16 @@
+name: hdf5 dev daily build on schedule
+
+# Triggers the workflow on a schedule or on demand
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "6 0 * * *"
+
+permissions:
+    contents: write # In order to allow tag creation and file deletion
+
+jobs:
+  daily-build:
+    uses: ./.github/workflows/daily-build.yml
+    with:
+      use_ignore: check
diff --git a/.github/workflows/main-cmake.yml b/.github/workflows/main-cmake.yml
index 9c58f0ba8e2..3c953409740 100644
--- a/.github/workflows/main-cmake.yml
+++ b/.github/workflows/main-cmake.yml
@@ -270,11 +270,3 @@ jobs:
               path: ${{ runner.workspace }}/build/HDF5-*-Darwin.tar.gz
               if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
         if: ${{ (matrix.os == 'macos-latest') && (inputs.thread_safety != 'TS') }}
-
-      - name: Save published dmg binary (Mac_latest)
-        uses: actions/upload-artifact@v4
-        with:
-              name: tgz-macos14_clang-${{ inputs.build_mode }}-dmg-binary
-              path: ${{ runner.workspace }}/build/HDF5-*-Darwin.dmg
-              if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
-        if: ${{ (matrix.os == 'macos-latest') && (inputs.thread_safety != 'TS') }}
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index e41b30c4d37..5f750a08f7e 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -55,7 +55,7 @@ jobs:
     needs: [log-the-inputs, call-workflow-tarball, call-workflow-ctest]
     uses: ./.github/workflows/abi-report.yml
     with:
-      file_ref: '1.14.4.3'
+      file_ref: '1.14.5'
       file_base: ${{ needs.call-workflow-tarball.outputs.file_base }}
       use_tag: ${{ needs.log-the-inputs.outputs.rel_tag }}
       use_environ: release
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2dc3af4a8ef..5522dc35aad 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -600,8 +600,10 @@ option (HDF5_ENABLE_COVERAGE "Enable code coverage for Libraries and Programs" O
 if (HDF5_ENABLE_COVERAGE)
   include (${HDF5_SOURCE_DIR}/config/sanitizer/code-coverage.cmake)
   if(CODE_COVERAGE AND CODE_COVERAGE_ADDED)
+    message(VERBOSE "Add instrumentation to all targets")
     add_code_coverage () # Adds instrumentation to all targets
   else ()
+    message(VERBOSE "Use --coverage option")
     set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -O0 --coverage -fprofile-arcs -ftest-coverage")
     set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g --coverage -O0 -fprofile-arcs -ftest-coverage")
     if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
diff --git a/README.md b/README.md
index 37c45ad022d..e5c4d917305 100644
--- a/README.md
+++ b/README.md
@@ -90,12 +90,10 @@ are tentative.
 
 | Release | New Features |
 | ------- | ------------ |
-| 1.14.5 | oss-fuzz fixes, ros3 VFD improvements |
-| 1.14.6 | Last maintenance release of 1.14 |
-| 1.16.0 | Complex number support, updated library defaults (cache sizes, etc.) |
-| 2.0.0 | Multi-threaded HDF5, crashproofing / metadata journaling, Full (VFD) SWMR, encryption, digital signatures, sparse datasets, improved storage for variable-length datatypes, better Unicode support (especially on Windows), semantic versioning |
+| 2.0.0 | Drop Autotools support, complex number support, updated library defaults (cache sizes, etc.), semantic versioning |
+| FUTURE | Multi-threaded HDF5, crashproofing / metadata journaling, Full (VFD) SWMR, encryption, digital signatures, sparse datasets, improved storage for variable-length datatypes, better Unicode support (especially on Windows) |
 
-Some HDF5 2.0.0 features listed here may be released in a 1.16.x release.
+NOTE: In the March 2025 release we will begin using semantic versioning (https://semver.org/) and the previously announced 1.16.0 version will instead be numbered 2.0.0.
 
 This list of feature release versions is also tentative, and the specific release
 in which a feature is introduced may change.
diff --git a/c++/test/tfile.cpp b/c++/test/tfile.cpp
index bd7d96422e8..7f3406a60b8 100644
--- a/c++/test/tfile.cpp
+++ b/c++/test/tfile.cpp
@@ -759,7 +759,7 @@ test_libver_bounds()
 
     /* Run the tests */
     test_libver_bounds_real(H5F_LIBVER_EARLIEST, H5O_VERSION_1, H5F_LIBVER_LATEST, H5O_VERSION_2);
-    test_libver_bounds_real(H5F_LIBVER_LATEST, H5O_VERSION_2, H5F_LIBVER_EARLIEST, H5O_VERSION_2);
+    test_libver_bounds_real(H5F_LIBVER_LATEST, H5O_VERSION_2, H5F_LIBVER_EARLIEST, H5O_VERSION_1);
     PASSED();
 } /* end test_libver_bounds() */
 
diff --git a/config/cmake/ConfigureChecks.cmake b/config/cmake/ConfigureChecks.cmake
index 6db82bb9229..c13334c5f8c 100644
--- a/config/cmake/ConfigureChecks.cmake
+++ b/config/cmake/ConfigureChecks.cmake
@@ -67,6 +67,8 @@ if (WIN32 AND NOT MINGW)
       set (${HDF_PREFIX}_HAVE_VISUAL_STUDIO 1)
     endif ()
   endif ()
+  message (TRACE "MSVC=${MSVC}")
+  message (TRACE "HAVE_VISUAL_STUDIO=${${HDF_PREFIX}_HAVE_VISUAL_STUDIO}")
 endif ()
 
 if (WINDOWS)
@@ -79,13 +81,12 @@ if (WINDOWS)
   endif ()
   if (NOT UNIX AND NOT CYGWIN)
     set (${HDF_PREFIX}_HAVE_GETCONSOLESCREENBUFFERINFO 1)
-    if (MSVC_VERSION GREATER_EQUAL 1900)
-      set (${HDF_PREFIX}_HAVE_TIMEZONE 1)
-    endif ()
+    set (${HDF_PREFIX}_HAVE_TIMEZONE 1)
     set (${HDF_PREFIX}_HAVE_GETTIMEOFDAY 1)
     set (${HDF_PREFIX}_HAVE_LIBWS2_32 1)
     set (${HDF_PREFIX}_HAVE_LIBWSOCK32 1)
   endif ()
+  message (TRACE "HAVE_TIMEZONE=${${HDF_PREFIX}_HAVE_TIMEZONE}")
 endif ()
 
 # ----------------------------------------------------------------------
diff --git a/config/sanitizer/code-coverage.cmake b/config/sanitizer/code-coverage.cmake
index 54a33deda3f..5249ed05af1 100644
--- a/config/sanitizer/code-coverage.cmake
+++ b/config/sanitizer/code-coverage.cmake
@@ -81,9 +81,13 @@ option(
 
 # Programs
 find_program(LLVM_COV_PATH llvm-cov)
+message(VERBOSE "program llvm-cov=${LLVM_COV_PATH}")
 find_program(LLVM_PROFDATA_PATH llvm-profdata)
+message(VERBOSE "program llvm-profdata=${LLVM_PROFDATA_PATH}")
 find_program(LCOV_PATH lcov)
+message(VERBOSE "program lcov=${LCOV_PATH}")
 find_program(GENHTML_PATH genhtml)
+message(VERBOSE "program genhtml=${GENHTML_PATH}")
 # Hide behind the 'advanced' mode flag for GUI/ccmake
 mark_as_advanced(FORCE LLVM_COV_PATH LLVM_PROFDATA_PATH LCOV_PATH GENHTML_PATH)
 
diff --git a/config/toolchain/intel.cmake b/config/toolchain/intel.cmake
index f8f60b28b46..f5b227ba2a0 100644
--- a/config/toolchain/intel.cmake
+++ b/config/toolchain/intel.cmake
@@ -4,7 +4,11 @@
 set(CMAKE_COMPILER_VENDOR "intel")
 
 set(CMAKE_C_COMPILER icx)
-set(CMAKE_CXX_COMPILER icpx)
+if(WIN32)
+ set(CMAKE_CXX_COMPILER icx)
+else()
+  set(CMAKE_CXX_COMPILER icpx)
+endif()
 set(CMAKE_Fortran_COMPILER ifx)
 
 # the following is used if cross-compiling
diff --git a/doc/img/release-schedule.plantuml b/doc/img/release-schedule.plantuml
index d0fd79b1426..c7e45c18b4c 100644
--- a/doc/img/release-schedule.plantuml
+++ b/doc/img/release-schedule.plantuml
@@ -23,26 +23,24 @@ Project starts 2023-01-01
 [1.12.3] happens 2023-11-30
 [1.12] is colored in #88CCEE
 
-[1.14] starts at 2023-01-01 and lasts 118 weeks
+[1.14] starts at 2023-01-01 and lasts 92 weeks
 [1.14.1] happens at 2023-04-30
 [1.14.2] happens at 2023-08-31
 [1.14.3] happens at 2023-10-31
 [1.14.4.2] happens at 2024-04-15
 [1.14.4.3] happens at 2024-05-22
 [1.14.5] happens at 2024-09-30
-[1.14.6] happens at 2025-03-31
 [1.14.1] displays on same row as [1.14.1]
 [1.14.2] displays on same row as [1.14.1]
 [1.14.3] displays on same row as [1.14.1]
 [1.14.4.2] displays on same row as [1.14.1]
 [1.14.5] displays on same row as [1.14.1]
-[1.14.6] displays on same row as [1.14.1]
 [1.14] is colored in #B187CF
 
-[1.16] starts at 2025-03-31 and lasts 35 weeks
-[1.16.0] happens at 2025-03-31
-[1.16.1] happens at 2025-09-30
-[1.16.1] displays on same row as [1.16.0]
-[1.16] is colored in #02BFA0
+[2.0] starts at 2024-09-30 and lasts 53 weeks
+[2.0.0] happens at 2025-03-31
+[2.1.0] happens at 2025-09-30
+[2.1.0] displays on same row as [2.0.0]
+[2.0] is colored in #02BFA0
 
 @endgantt
diff --git a/doc/img/release-schedule.png b/doc/img/release-schedule.png
index 20a0a55986d..ec65bfa595d 100644
Binary files a/doc/img/release-schedule.png and b/doc/img/release-schedule.png differ
diff --git a/fortran/src/H5Rff.F90 b/fortran/src/H5Rff.F90
index cad9d3c8a0e..75933e28fb4 100644
--- a/fortran/src/H5Rff.F90
+++ b/fortran/src/H5Rff.F90
@@ -856,13 +856,13 @@ INTEGER(C_INT) FUNCTION H5Requal(ref1_ptr, ref2_ptr) &
        END FUNCTION H5Requal
     END INTERFACE
 
-    c_equal = INT(H5Requal(ref1_ptr, ref2_ptr))
+    c_equal = INT(H5Requal(ref1_ptr, ref2_ptr), C_INT)
 
     hdferr = 0
     equal = .FALSE.
-    IF(c_equal .EQ. 1)THEN
+    IF(c_equal .EQ. 1_C_INT)THEN
        equal = .TRUE.
-    ELSE IF(c_equal .LT. 0)THEN
+    ELSE IF(c_equal .LT. 0_C_INT)THEN
        hdferr = -1
     ENDIF
 
diff --git a/fortran/src/H5VLff.F90 b/fortran/src/H5VLff.F90
index b07e1389f21..e1629328ce2 100644
--- a/fortran/src/H5VLff.F90
+++ b/fortran/src/H5VLff.F90
@@ -419,7 +419,8 @@ SUBROUTINE H5VLcmp_connector_cls_f(are_same, conn_id1, conn_id2, hdferr)
     INTEGER(HID_T), INTENT(IN) :: conn_id1
     INTEGER(HID_T), INTENT(IN) :: conn_id2
     INTEGER, INTENT(OUT) :: hdferr
-    INTEGER :: are_same_c
+
+    INTEGER(C_INT) :: are_same_c
 
     INTERFACE
        INTEGER(C_INT) FUNCTION H5VLcmp_connector_cls(cmp_value, conn_id1, conn_id2) BIND(C, NAME='H5VLcmp_connector_cls')
@@ -432,7 +433,7 @@ END FUNCTION H5VLcmp_connector_cls
 
     are_same = .FALSE.
     hdferr = INT(H5VLcmp_connector_cls(are_same_c, conn_id1, conn_id2))
-    IF(are_same_c .EQ. 0) are_same = .TRUE.
+    IF(are_same_c .EQ. 0_C_INT) are_same = .TRUE.
 
   END SUBROUTINE H5VLcmp_connector_cls_f
 
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 36de830a71c..cf9b65cc086 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -132,7 +132,19 @@ Bug Fixes since HDF5-1.16.0 release
 ===================================
     Library
     -------
-    -
+    - Only clear FE_INVALID when that symbol is present on the system
+
+      When we initialize the floating-point types at library startup, it's
+      possible to raise floating-point exceptions when we check which things
+      are supported. Normally, we clear these floating-point exceptions via
+      feclearexcept(FE_INVALID), but FE_INVALID may not be present on all
+      systems. Specifically, this was reported as being a problem when using
+      Emscripten 3.1.68 to compile HDF5 1.14.5 to WebAssembly.
+
+      We've added an #ifdef FE_INVALID block around the exception clearing
+      code to correct this.
+
+      Fixes GitHub issue #4952
 
 
     Java Library
diff --git a/src/H5Fint.c b/src/H5Fint.c
index add4bcfc043..9fc0499ad9a 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -3213,7 +3213,8 @@ H5F__set_libver_bounds(H5F_t *f, H5F_libver_t low, H5F_libver_t high)
     assert(f->shared);
 
     /* Set the bounds only if the existing setting is different from the inputs */
-    if (f->shared->low_bound != low || f->shared->high_bound != high) {
+    if ((f->shared->low_bound != low || f->shared->high_bound != high) &&
+        !(H5F_INTENT(f) & H5F_ACC_SWMR_WRITE)) {
         /* Call the flush routine, for this file */
         /* Note: This is done in case the binary format for representing a
          *      metadata entry class changes when the file format low / high
@@ -3736,6 +3737,7 @@ H5F_get_metadata_read_retry_info(H5F_t *file, H5F_retry_info_t *info)
  *                  --only allow datasets and groups without attributes
  *                  --disallow named datatype with/without attributes
  *                  --disallow opened attributes attached to objects
+ *                  --disallow opened objects below 1.10
  *
  * NOTE:        Currently, only opened groups and datasets are allowed
  *              when enabling SWMR via H5Fstart_swmr_write().
@@ -3778,7 +3780,7 @@ H5F__start_swmr_write(H5F_t *f)
     if (f->shared->sblock->super_vers < HDF5_SUPERBLOCK_VERSION_3)
         HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "file superblock version - should be at least 3");
 
-    /* Check for correct file format version */
+    /* Check for correct file format version to start SWMR writing */
     if ((f->shared->low_bound < H5F_LIBVER_V110) || (f->shared->high_bound < H5F_LIBVER_V110))
         HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL,
                     "file format version does not support SWMR - needs to be 1.10 or greater");
@@ -3815,6 +3817,31 @@ H5F__start_swmr_write(H5F_t *f)
         /* Allocate space for group and object locations */
         if ((obj_ids = (hid_t *)H5MM_malloc(grp_dset_count * sizeof(hid_t))) == NULL)
             HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "can't allocate buffer for hid_t");
+
+        /* Get the list of opened object ids (groups & datasets) */
+        if (H5F_get_obj_ids(f, H5F_OBJ_GROUP | H5F_OBJ_DATASET, grp_dset_count, obj_ids, false,
+                            &grp_dset_count) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "H5F_get_obj_ids failed");
+
+        /* Ensure that there's no old-style opened objects */
+        for (u = 0; u < grp_dset_count; u++) {
+            H5O_native_info_t ninfo;
+            H5O_loc_t        *oloc;
+            uint8_t           version;
+
+            if (NULL == (oloc = H5O_get_loc(obj_ids[u])))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "H5O_get_loc() failed");
+
+            if (H5O_get_native_info(oloc, &ninfo, H5O_NATIVE_INFO_HDR) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "H5O_get_native_info() failed");
+
+            if (H5O_get_version_bound(f->shared->low_bound, &version) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "H5O_get_version_bound() failed");
+
+            if (ninfo.hdr.version < version)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "disallow opened objects below 1.10");
+        }
+
         if ((obj_glocs = (H5G_loc_t *)H5MM_malloc(grp_dset_count * sizeof(H5G_loc_t))) == NULL)
             HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "can't allocate buffer for object group locations");
         if ((obj_olocs = (H5O_loc_t *)H5MM_malloc(grp_dset_count * sizeof(H5O_loc_t))) == NULL)
@@ -3829,11 +3856,6 @@ H5F__start_swmr_write(H5F_t *f)
             HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "can't allocate buffer for hid_t");
         assert(obj_apl_ids[0] == H5P_DEFAULT);
 
-        /* Get the list of opened object ids (groups & datasets) */
-        if (H5F_get_obj_ids(f, H5F_OBJ_GROUP | H5F_OBJ_DATASET, grp_dset_count, obj_ids, false,
-                            &grp_dset_count) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "H5F_get_obj_ids failed");
-
         /* Save the VOL connector and the object wrapping context for the refresh step */
         if (grp_dset_count > 0) {
             H5VL_object_t *vol_obj;
diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index 39c92f34b17..28b21ed01b3 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -432,45 +432,27 @@ H5F__super_read(H5F_t *f, H5P_genplist_t *fa_plist, bool initial_read)
         HGOTO_ERROR(H5E_FILE, H5E_CANTPROTECT, FAIL, "unable to load superblock");
 
     /*
-     * When opening a file with SWMR-write access, the library will first
-     * check to ensure that superblock version 3 is used.  Otherwise fail
-     * file open.
-     *
-     * Then the library will upgrade the file's low_bound depending on
-     * superblock version as follows:
-     *      --version 0 or 1: no change to low_bound
-     *      --version 2: upgrade low_bound to at least V18
-     *      --version 3: upgrade low_bound to at least V110
+     * When opening a file with SWMR-write access, the library will check to
+     * ensure that:
+     *      --superblock version 3 is used
+     *      --superblock version does not exceed the version allowed by high bound
+     *      --upgrade low_bound to at least V110
+     * Otherwise fail file open for SMWR-write access
      *
      * Upgrading low_bound will give the best format versions available for
      * that superblock version.  Due to the possible upgrade, the fapl returned
      * from H5Fget_access_plist() might indicate a low_bound higher than what
      * the user originally set.
      *
-     * After upgrading low_bound, the library will check to ensure that the
-     * superblock version does not exceed the version allowed by high_bound.
-     * Otherwise fail file open.
-     *
      * For details, please see RFC:Setting Bounds for Object Creation in HDF5 1.10.0.
      */
-
-    /* Check to ensure that superblock version 3 is used for SWMR-write access */
     if (H5F_INTENT(f) & H5F_ACC_SWMR_WRITE) {
         if (sblock->super_vers < HDF5_SUPERBLOCK_VERSION_3)
             HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "superblock version for SWMR is less than 3");
-    }
-
-    /* Upgrade low_bound to at least V18 when encountering version 2 superblock */
-    if (sblock->super_vers == HDF5_SUPERBLOCK_VERSION_2)
-        f->shared->low_bound = MAX(H5F_LIBVER_V18, f->shared->low_bound);
-
-    /* Upgrade low_bound to at least V110 when encountering version 3 superblock */
-    if (sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_3)
+        if (sblock->super_vers > HDF5_superblock_ver_bounds[f->shared->high_bound])
+            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "superblock version exceeds high bound");
         f->shared->low_bound = MAX(H5F_LIBVER_V110, f->shared->low_bound);
-
-    /* Version bounds check */
-    if (sblock->super_vers > HDF5_superblock_ver_bounds[f->shared->high_bound])
-        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "superblock version exceeds high bound");
+    }
 
     /* Pin the superblock in the cache */
     if (H5AC_pin_protected_entry(sblock) < 0)
diff --git a/src/H5Oint.c b/src/H5Oint.c
index cca6ccd161a..2ac622dd106 100644
--- a/src/H5Oint.c
+++ b/src/H5Oint.c
@@ -2984,3 +2984,20 @@ H5O_has_chksum(const H5O_t *oh)
 
     FUNC_LEAVE_NOAPI(H5O_SIZEOF_CHKSUM_OH(oh) > 0)
 } /* end H5O_has_chksum() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_get_version_bound
+ *
+ * Purpose:     Retrieve the version for a given bound from object version array
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_get_version_bound(H5F_libver_t bound, uint8_t *version)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    *version = (uint8_t)H5O_obj_ver_bounds[bound];
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5O_get_version_bound() */
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index a5eebcf3985..4b1f4e07940 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -933,6 +933,7 @@ H5_DLL uint8_t H5O_get_oh_version(const H5O_t *oh);
 H5_DLL herr_t  H5O_get_rc_and_type(const H5O_loc_t *oloc, unsigned *rc, H5O_type_t *otype);
 H5_DLL H5AC_proxy_entry_t *H5O_get_proxy(const H5O_t *oh);
 H5_DLL bool                H5O_has_chksum(const H5O_t *oh);
+H5_DLL herr_t              H5O_get_version_bound(H5F_libver_t bound, uint8_t *version);
 
 /* Object header message routines */
 H5_DLL herr_t H5O_msg_create(const H5O_loc_t *loc, unsigned type_id, unsigned mesg_flags,
diff --git a/src/H5Tinit_float.c b/src/H5Tinit_float.c
index de959b49735..39deda03625 100644
--- a/src/H5Tinit_float.c
+++ b/src/H5Tinit_float.c
@@ -608,9 +608,13 @@ H5T__init_native_float_types(void)
 #endif
 
 done:
-    /* Clear any FE_INVALID exceptions from NaN handling */
+    /* Clear any FE_INVALID exceptions from NaN handling. FE_INVALID is C99/C11,
+     * but may not be present on all systems.
+     */
+#ifdef FE_INVALID
     if (feclearexcept(FE_INVALID) != 0)
         HSYS_GOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "can't clear floating-point exceptions");
+#endif
 
     /* Restore the original environment */
     if (feupdateenv(&saved_fenv) != 0)
diff --git a/src/H5VLpassthru.c b/src/H5VLpassthru.c
index 8c1de0e6d96..14274ed86c9 100644
--- a/src/H5VLpassthru.c
+++ b/src/H5VLpassthru.c
@@ -49,13 +49,6 @@
 /* (Uncomment to enable) */
 /* #define ENABLE_PASSTHRU_LOGGING */
 
-/* Hack for missing va_copy() in old Visual Studio editions
- * (from H5win2_defs.h - used on VS2012 and earlier)
- */
-#if defined(_WIN32) && defined(_MSC_VER) && (_MSC_VER < 1800)
-#define va_copy(D, S) ((D) = (S))
-#endif
-
 /************/
 /* Typedefs */
 /************/
diff --git a/src/H5system.c b/src/H5system.c
index 21135bc5da9..2da53d82e55 100644
--- a/src/H5system.c
+++ b/src/H5system.c
@@ -173,14 +173,10 @@ Nflock(int H5_ATTR_UNUSED fd, int H5_ATTR_UNUSED operation)
 time_t
 H5_make_time(struct tm *tm)
 {
-    time_t the_time;                                     /* The converted time */
-#if defined(H5_HAVE_VISUAL_STUDIO) && (_MSC_VER >= 1900) /* VS 2015 */
-    /* In gcc and in Visual Studio prior to VS 2015 'timezone' is a global
-     * variable declared in time.h. That variable was deprecated and in
-     * VS 2015 is removed, with _get_timezone replacing it.
-     */
+    time_t the_time; /* The converted time */
+#if defined(H5_HAVE_VISUAL_STUDIO)
     long timezone = 0;
-#endif                    /* defined(H5_HAVE_VISUAL_STUDIO) && (_MSC_VER >= 1900) */
+#endif
     time_t ret_value = 0; /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -203,13 +199,9 @@ H5_make_time(struct tm *tm)
     /* BSD-like systems */
     the_time += tm->tm_gmtoff;
 #elif defined(H5_HAVE_TIMEZONE)
-#if defined(H5_HAVE_VISUAL_STUDIO) && (_MSC_VER >= 1900) /* VS 2015 */
-    /* In gcc and in Visual Studio prior to VS 2015 'timezone' is a global
-     * variable declared in time.h. That variable was deprecated and in
-     * VS 2015 is removed, with _get_timezone replacing it.
-     */
+#if defined(H5_HAVE_VISUAL_STUDIO)
     _get_timezone(&timezone);
-#endif /* defined(H5_HAVE_VISUAL_STUDIO) && (_MSC_VER >= 1900) */
+#endif
 
     the_time -= timezone - (tm->tm_isdst ? 3600 : 0);
 #else
diff --git a/test/swmr.c b/test/swmr.c
index cb99917756a..ce9d73e272c 100644
--- a/test/swmr.c
+++ b/test/swmr.c
@@ -1554,20 +1554,26 @@ test_metadata_read_retry_info(hid_t in_fapl)
  *      Should fail to enable SWMR as the file is already in SWMR writing mode
  *      Close the file
  *
- *  (B) Opening a file
- *      Open the file with write + non-latest-format
- *      --file has v3 superblock and all latest version support enabled
- *      Open dataset "dataset1" 3 times--keep it open
- *    Write to "dataset1"
- *    Create a group in the file
- *      Create a chunked dataset "dataset2" in the group--should be using latest chunk indexing--keep it open
- *      Should succeed in enabling SWMR
- *    Should succeed in reading from multiple opens of "dataset1"
- *      Close multiple opens of "dataset1"
- *    Close "dataset2"
- *      Create "dataset3"--should be using latest chunk indexing
- *      Close "dataset3"
- *      Close the group and file
+ *  (B) Open the file with write + non-latest-format (earliest, latest)
+ *      --file has v3 superblock
+ *      Create a group in the file
+ *      Create a chunked dataset "dataset2" in the group--keep it open
+ *      Verify "dataset2" is using v1 btree indexing
+ *      Should fail to enable SWMR writing
+ *
+ *  (C) Open a file with write + non-latest format (V110, latest)
+ *      Open the old style group "/group/dataset2" in the file
+ *      Should fail to enable SWMR writing
+ *
+ *  (D) Open a file with write + non-latest format (V110, latest)
+ *      Open the old style group "/group"
+ *      Open the new style group "/dataset1" in the file
+ *      Should fail to enable SWMR writing
+ *
+ *  (E) Open a file with write + non-latest format (V110, latest)
+ *      Open the new style group "/dataset1" in the file
+ *      Should succeed to enable SWMR writing
+ *
  */
 static int
 test_start_swmr_write(hid_t in_fapl, bool new_format)
@@ -1707,11 +1713,11 @@ test_start_swmr_write(hid_t in_fapl, bool new_format)
         FAIL_STACK_ERROR;
 
     /*
-     * Case B: when opening a file
+     * Case B: when opening a file with (earliest, latest)
      */
 
-    /* Open the file again with write + non-latest-format */
-    if ((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
+    /* Open the file again with write + non-latest-format (earliest, latest) */
+    if ((fid = H5Fopen(filename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
         FAIL_STACK_ERROR;
 
     /* Get the file's access_property list */
@@ -1730,23 +1736,6 @@ test_start_swmr_write(hid_t in_fapl, bool new_format)
     if (H5Pclose(file_fapl) < 0)
         FAIL_STACK_ERROR;
 
-    /* open "dataset1", keep it open */
-    if ((did1 = H5Dopen2(fid, "dataset1", H5P_DEFAULT)) < 0)
-        FAIL_STACK_ERROR;
-
-    /* open "dataset1" second time */
-    if ((did1_a = H5Dopen2(fid, "dataset1", H5P_DEFAULT)) < 0)
-        FAIL_STACK_ERROR;
-
-    /* open "dataset1" third time */
-    if ((did1_b = H5Dopen2(fid, "dataset1", H5P_DEFAULT)) < 0)
-        FAIL_STACK_ERROR;
-
-    /* Write to "dataset1" */
-    wdata = 88;
-    if (H5Dwrite(did1, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &wdata) < 0)
-        FAIL_STACK_ERROR;
-
     /* Create a group */
     if ((gid = H5Gcreate2(fid, "group", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         FAIL_STACK_ERROR;
@@ -1764,99 +1753,112 @@ test_start_swmr_write(hid_t in_fapl, bool new_format)
     /* Get the chunk index type for "dataset2" */
     if (H5D__layout_idx_type_test(did2, &idx_type) < 0)
         FAIL_STACK_ERROR;
-    if (idx_type != H5D_CHUNK_IDX_BT2)
-        FAIL_PUTS_ERROR("should be using v2 B-tree chunk indexing");
-
-    /* Should succeed in enabling SWMR writing */
-    if (H5Fstart_swmr_write(fid) < 0)
-        FAIL_STACK_ERROR;
-
-    /* Get the file's access_property list */
-    if ((file_fapl = H5Fget_access_plist(fid)) < 0)
-        FAIL_STACK_ERROR;
+    if (idx_type != H5D_CHUNK_IDX_BTREE)
+        FAIL_PUTS_ERROR("should be using v1 B-tree chunk indexing");
 
-    /* Retrieve the # of read attempts */
-    if (H5Pget_metadata_read_attempts(file_fapl, &attempts) < 0)
-        FAIL_STACK_ERROR;
+    /* Should fail in enabling SWMR writing since file is opened with (earliest/latest) */
+    H5E_BEGIN_TRY
+    {
+        ret = H5Fstart_swmr_write(fid);
+    }
+    H5E_END_TRY
+    if (ret >= 0)
+        TEST_ERROR;
 
-    /* Should be 100 */
-    if (attempts != H5F_SWMR_METADATA_READ_ATTEMPTS)
+    if (H5Gclose(gid) < 0)
+        TEST_ERROR;
+    if (H5Dclose(did2) < 0)
+        TEST_ERROR;
+    if (H5Fclose(fid) < 0)
         TEST_ERROR;
 
-    /* Close the property list */
-    if (H5Pclose(file_fapl) < 0)
-        FAIL_STACK_ERROR;
+    /*
+     * Case C: when opening a file with (V110, latest)
+     */
 
-    rdata = 0;
-    /* Read from "dataset1" via did1_b (multiple opens) */
-    if (H5Dread(did1_b, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &rdata) < 0)
-        FAIL_STACK_ERROR;
-    if (wdata != rdata)
-        FAIL_STACK_ERROR;
-    if (H5Dclose(did1_b) < 0)
+    if (H5Pset_libver_bounds(fapl, H5F_LIBVER_V110, H5F_LIBVER_LATEST) < 0)
         FAIL_STACK_ERROR;
 
-    /* Read from "dataset1" */
-    rdata = 0;
-    if (H5Dread(did1, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &rdata) < 0)
-        FAIL_STACK_ERROR;
-    if (wdata != rdata)
-        FAIL_STACK_ERROR;
-    if (H5Dclose(did1) < 0)
+    /* Open the file again with write + non-latest-format (V110, latest) */
+    if ((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
         FAIL_STACK_ERROR;
 
-    rdata = 0;
-    /* Read from "dataset1" via did1_a (multiple opens) */
-    if (H5Dread(did1_a, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &rdata) < 0)
-        FAIL_STACK_ERROR;
-    if (wdata != rdata)
+    /* Open the old style dataset: /group/datset2 */
+    if ((did2 = H5Dopen2(fid, "/group/dataset2", H5P_DEFAULT)) < 0)
         FAIL_STACK_ERROR;
-    if (H5Dclose(did1_a) < 0)
+
+    /* Open the new style dataset */
+    if ((did1 = H5Dopen2(fid, "dataset1", H5P_DEFAULT)) < 0)
         FAIL_STACK_ERROR;
 
-    /* Close "dataset2", dataspace, dataset creation property list */
+    /* Should fail in enabling SWMR writing since there are old style objects opened  */
+    H5E_BEGIN_TRY
+    {
+        ret = H5Fstart_swmr_write(fid);
+    }
+    H5E_END_TRY
+    if (ret >= 0)
+        TEST_ERROR;
+
     if (H5Dclose(did2) < 0)
-        FAIL_STACK_ERROR;
-    if (H5Sclose(sid2) < 0)
-        FAIL_STACK_ERROR;
-    if (H5Pclose(dcpl) < 0)
-        FAIL_STACK_ERROR;
+        TEST_ERROR;
+    if (H5Dclose(did1) < 0)
+        TEST_ERROR;
+    if (H5Fclose(fid) < 0)
+        TEST_ERROR;
 
-    /* Create "dataset3" */
-    if ((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
-        FAIL_STACK_ERROR;
-    if (H5Pset_chunk(dcpl, 2, chunk_dim2) < 0)
-        FAIL_STACK_ERROR;
-    if ((sid3 = H5Screate_simple(2, dim2, max_dim2)) < 0)
-        FAIL_STACK_ERROR;
-    if ((did3 = H5Dcreate2(fid, "dataset3", H5T_NATIVE_INT, sid3, H5P_DEFAULT, dcpl, H5P_DEFAULT)) < 0)
-        FAIL_STACK_ERROR;
+    /*
+     * Case D: when opening a file with (V110, latest)
+     */
 
-    /* Get the chunk index type for "dataset3" */
-    if (H5D__layout_idx_type_test(did3, &idx_type) < 0)
+    /* Open the file again with write + non-latest-format (V110, latest) */
+    if ((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
         FAIL_STACK_ERROR;
-    if (idx_type != H5D_CHUNK_IDX_BT2)
-        FAIL_PUTS_ERROR("should be using v2 B-tree as index");
 
-    /* Close "dataset3", dataspace, dataset creation property list */
-    if (H5Dclose(did3) < 0)
-        FAIL_STACK_ERROR;
-    if (H5Sclose(sid3) < 0)
+    /* Open the old style group: /group */
+    if ((gid = H5Gopen2(fid, "group", H5P_DEFAULT)) < 0)
         FAIL_STACK_ERROR;
-    if (H5Pclose(dcpl) < 0)
+
+    /* Open the new style dataset */
+    if ((did1 = H5Dopen2(fid, "dataset1", H5P_DEFAULT)) < 0)
         FAIL_STACK_ERROR;
 
-    /* Close the group */
+    /* Should fail in enabling SWMR writing since there are old style objects opened  */
+    H5E_BEGIN_TRY
+    {
+        ret = H5Fstart_swmr_write(fid);
+    }
+    H5E_END_TRY
+    if (ret >= 0)
+        TEST_ERROR;
+
     if (H5Gclose(gid) < 0)
+        TEST_ERROR;
+    if (H5Dclose(did1) < 0)
+        TEST_ERROR;
+    if (H5Fclose(fid) < 0)
+        TEST_ERROR;
+
+    /*
+     * Case E: when opening a file with (V110, latest)
+     */
+
+    /* Open the file again with write + non-latest-format (V110, latest) */
+    if ((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
         FAIL_STACK_ERROR;
 
-    /* Close the file access property list */
-    if (H5Pclose(fapl) < 0)
+    /* Open the new style dataset */
+    if ((did1 = H5Dopen2(fid, "dataset1", H5P_DEFAULT)) < 0)
         FAIL_STACK_ERROR;
 
-    /* Close the file */
+    /* Should succeed in enabling SWMR writing */
+    if (H5Fstart_swmr_write(fid) < 0)
+        TEST_ERROR;
+
+    if (H5Dclose(did1) < 0)
+        TEST_ERROR;
     if (H5Fclose(fid) < 0)
-        FAIL_STACK_ERROR;
+        TEST_ERROR;
 
     PASSED();
 
@@ -1915,12 +1917,12 @@ test_start_swmr_write(hid_t in_fapl, bool new_format)
  *      --Enable SWMR writing mode twice
  *      --First time succeed, second time fail
  *      --Close the file
-        (2) --Open the file with write + with/without latest format
+ *      (2) --Open the file with write + with/without latest format
  *      --Succeed to enable SWMR writing mode
  *      --Reopen the same file
  *          --fail to enable SWMR writing mode for the reopened file
  *      --Close the file
-        (3) --Open the file with write + with/without latest format
+ *      (3) --Open the file with write + with/without latest format
  *      --Open the same file again
  *          --succeed to enable SWMR for the first opened file
  *          --fail to enable SWMR for the second opened file
@@ -1931,7 +1933,6 @@ test_start_swmr_write(hid_t in_fapl, bool new_format)
  *              --fail to open due to superblock version not 3
  *          (2) Open the file with SWMR write+non-latest-format
  *              --fail to open due to superblock version not 3
-
  *          (3) Open the file with write+latest format
  *              --fail to enable SWMR due to superblock version not 3
  *          (4) Open the file with write+non-latest-format
@@ -2164,8 +2165,18 @@ test_err_start_swmr_write(hid_t in_fapl, bool new_format)
     if (H5Aclose(aid) < 0)
         FAIL_STACK_ERROR;
 
-    /* Should succeed in enabling SWMR writing */
-    if (H5Fstart_swmr_write(fid) < 0)
+    /* Should succeed in enabling SWMR writing when new_format */
+    /* Should fail in enabling SWMR writing when !new_format */
+    H5E_BEGIN_TRY
+    {
+        ret = H5Fstart_swmr_write(fid);
+    }
+    H5E_END_TRY
+    if (new_format) {
+        if (ret < 0)
+            TEST_ERROR;
+    }
+    else if (ret >= 0)
         TEST_ERROR;
 
     /* Close the dataspace */
@@ -2195,8 +2206,18 @@ test_err_start_swmr_write(hid_t in_fapl, bool new_format)
     if ((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
         FAIL_STACK_ERROR;
 
-    /* Should succeed in enabling SWMR writing mode */
-    if (H5Fstart_swmr_write(fid) < 0)
+    /* Should succeed when new_format */
+    /* Should fail when !new_format */
+    H5E_BEGIN_TRY
+    {
+        ret = H5Fstart_swmr_write(fid);
+    }
+    H5E_END_TRY
+    if (new_format) {
+        if (ret < 0)
+            TEST_ERROR;
+    }
+    else if (ret >= 0)
         TEST_ERROR;
 
     /* Should fail for a second call to enable SWMR writing mode */
@@ -2218,8 +2239,18 @@ test_err_start_swmr_write(hid_t in_fapl, bool new_format)
     if ((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
         FAIL_STACK_ERROR;
 
-    /* Should succeed in enabling SWMR writing mode */
-    if (H5Fstart_swmr_write(fid) < 0)
+    /* Should succeed when new_format */
+    /* Should fail when !new_format */
+    H5E_BEGIN_TRY
+    {
+        ret = H5Fstart_swmr_write(fid);
+    }
+    H5E_END_TRY
+    if (new_format) {
+        if (ret < 0)
+            TEST_ERROR;
+    }
+    else if (ret >= 0)
         TEST_ERROR;
 
     /* Re-open the same file */
@@ -2251,8 +2282,18 @@ test_err_start_swmr_write(hid_t in_fapl, bool new_format)
     if ((fid2 = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
         FAIL_STACK_ERROR;
 
-    /* Should succeed in enabling SWMR writing for fid */
-    if (H5Fstart_swmr_write(fid) < 0)
+    /* Should succeed when new_format */
+    /* Should fail when !new_format */
+    H5E_BEGIN_TRY
+    {
+        ret = H5Fstart_swmr_write(fid);
+    }
+    H5E_END_TRY
+    if (new_format) {
+        if (ret < 0)
+            TEST_ERROR;
+    }
+    else if (ret >= 0)
         TEST_ERROR;
 
     /* Should fail to enable SWMR writing for fid2 */
@@ -2500,6 +2541,11 @@ test_start_swmr_write_concur(hid_t in_fapl, bool new_format)
      *  will fail without H5Fstart_swmr_write()
      */
 
+    if (!new_format) {
+        if (H5Pset_libver_bounds(fapl, H5F_LIBVER_V110, H5F_LIBVER_LATEST) < 0)
+            FAIL_STACK_ERROR;
+    }
+
     /* Fork child process */
     if ((childpid = fork()) < 0)
         FAIL_STACK_ERROR;
@@ -7429,6 +7475,11 @@ test_multiple_same(hid_t in_fapl, bool new_format)
     if ((fapl = H5Pcopy(in_fapl)) < 0)
         FAIL_STACK_ERROR;
 
+    if (!new_format) {
+        if (H5Pset_libver_bounds(fapl, H5F_LIBVER_V110, H5F_LIBVER_LATEST) < 0)
+            FAIL_STACK_ERROR;
+    }
+
     /* Set the filename to use for this test (dependent on fapl) */
     h5_fixname(FILENAME[0], fapl, filename, sizeof(filename));
 
diff --git a/test/tfile.c b/test/tfile.c
index 0915ef78ba3..9ffedc0f001 100644
--- a/test/tfile.c
+++ b/test/tfile.c
@@ -5649,19 +5649,18 @@ test_libver_bounds_real(H5F_libver_t libver_create, unsigned oh_vers_create, H5F
  *
  *-------------------------------------------------------------------------
  */
-#define VERBFNAME   "tverbounds_dspace.h5"
+#define VFNAME      "verbounds.h5"
 #define VERBDSNAME  "dataset 1"
 #define SPACE1_DIM1 3
 static void
 test_libver_bounds_open(void)
 {
-    hid_t        file     = H5I_INVALID_HID;   /* File ID */
-    hid_t        space    = H5I_INVALID_HID;   /* Dataspace ID */
-    hid_t        dset     = H5I_INVALID_HID;   /* Dataset ID */
-    hid_t        fapl     = H5I_INVALID_HID;   /* File access property list ID */
-    hid_t        new_fapl = H5I_INVALID_HID;   /* File access property list ID for reopened file */
-    hid_t        dcpl     = H5I_INVALID_HID;   /* Dataset creation property list ID */
-    hsize_t      dim[1]   = {SPACE1_DIM1};     /* Dataset dimensions */
+    hid_t        file   = H5I_INVALID_HID;     /* File ID */
+    hid_t        space  = H5I_INVALID_HID;     /* Dataspace ID */
+    hid_t        dset   = H5I_INVALID_HID;     /* Dataset ID */
+    hid_t        fapl   = H5I_INVALID_HID;     /* File access property list ID */
+    hid_t        dcpl   = H5I_INVALID_HID;     /* Dataset creation property list ID */
+    hsize_t      dim[1] = {SPACE1_DIM1};       /* Dataset dimensions */
     H5F_libver_t low, high;                    /* File format bounds */
     hsize_t      chunk_dim[1] = {SPACE1_DIM1}; /* Chunk dimensions */
     bool         vol_is_native;
@@ -5707,7 +5706,7 @@ test_libver_bounds_open(void)
     CHECK(ret, FAIL, "H5Pset_libver_bounds");
 
     /* Create the file */
-    file = H5Fcreate(VERBFNAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
+    file = H5Fcreate(VFNAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
     CHECK(file, FAIL, "H5Fcreate");
 
     /* Create dataset */
@@ -5720,49 +5719,36 @@ test_libver_bounds_open(void)
     ret = H5Fclose(file);
     CHECK(ret, FAIL, "H5Fclose");
 
-    /* Attempt to open latest file with (earliest, v18), should fail */
+    /* Attempt to open latest file with (earliest, v18) should succeed */
     ret = H5Pset_libver_bounds(fapl, H5F_LIBVER_EARLIEST, H5F_LIBVER_V18);
-    H5E_BEGIN_TRY
-    {
-        file = H5Fopen(VERBFNAME, H5F_ACC_RDONLY, fapl);
-    }
-    H5E_END_TRY
-    VERIFY(file, FAIL, "Attempted to open latest file with earliest version");
+    CHECK(ret, FAIL, "H5Pset_libver_bounds");
+
+    if ((file = H5Fopen(VFNAME, H5F_ACC_RDONLY, fapl)) < 0)
+        VERIFY((file >= 0), true, "Attempt to open latest file with earliest version should succeed");
+    ret = H5Fclose(file);
+    CHECK(ret, FAIL, "H5Fclose");
 
     /* Attempt to open latest file with (v18, v18), should fail */
     ret = H5Pset_libver_bounds(fapl, H5F_LIBVER_V18, H5F_LIBVER_V18);
-    H5E_BEGIN_TRY
-    {
-        file = H5Fopen(VERBFNAME, H5F_ACC_RDONLY, fapl);
-    }
-    H5E_END_TRY
-    VERIFY(file, FAIL, "Attempted to open latest file with v18 bounds");
+    CHECK(ret, FAIL, "H5Pset_libver_bounds");
+
+    file = H5Fopen(VFNAME, H5F_ACC_RDONLY, fapl);
+    VERIFY((file >= 0), true, "Attempt to open latest file with v18 bounds should succeed");
+    ret = H5Fclose(file);
+    CHECK(ret, FAIL, "H5Fclose");
 
-    /* Opening VERBFNAME in these combination should succeed.
-       For each low bound, verify that it is upgraded properly */
+    /* Opening VERBFNAME in these combination should succeed */
     high = H5F_LIBVER_LATEST;
     for (low = H5F_LIBVER_EARLIEST; low < H5F_LIBVER_NBOUNDS; low++) {
-        H5F_libver_t new_low = H5F_LIBVER_EARLIEST;
 
         /* Set version bounds for opening file */
         ret = H5Pset_libver_bounds(fapl, low, high);
         CHECK(ret, FAIL, "H5Pset_libver_bounds");
 
         /* Open the file */
-        file = H5Fopen(VERBFNAME, H5F_ACC_RDONLY, fapl);
-        CHECK(file, FAIL, "H5Fopen");
-
-        /* Get the new file access property */
-        new_fapl = H5Fget_access_plist(file);
-        CHECK(new_fapl, FAIL, "H5Fget_access_plist");
-
-        /* Get new low bound and verify that it has been upgraded properly */
-        ret = H5Pget_libver_bounds(new_fapl, &new_low, NULL);
-        CHECK(ret, FAIL, "H5Pget_libver_bounds");
-        VERIFY(new_low >= H5F_LIBVER_V110, true, "Low bound should be upgraded to at least H5F_LIBVER_V110");
+        file = H5Fopen(VFNAME, H5F_ACC_RDONLY, fapl);
+        VERIFY(file >= 0, true, "H5Fopen should succeed");
 
-        ret = H5Pclose(new_fapl);
-        CHECK(ret, FAIL, "H5Pclose");
         ret = H5Fclose(file);
         CHECK(ret, FAIL, "H5Fclose");
     } /* for low */
@@ -5886,9 +5872,10 @@ test_libver_bounds(void)
 
     /* Run the tests */
     test_libver_bounds_real(H5F_LIBVER_EARLIEST, 1, H5F_LIBVER_LATEST, 2);
-    test_libver_bounds_real(H5F_LIBVER_LATEST, 2, H5F_LIBVER_EARLIEST, 2);
+    test_libver_bounds_real(H5F_LIBVER_LATEST, 2, H5F_LIBVER_EARLIEST, 1);
     test_libver_bounds_open();
     test_libver_bounds_copy();
+
 } /* end test_libver_bounds() */
 
 /**************************************************************************************
@@ -6251,7 +6238,7 @@ test_libver_bounds_super_create(hid_t fapl, hid_t fcpl, htri_t is_swmr, htri_t n
 **
 **                      (A) Opening a file with write access
 **
-**                                              Superblock version 0, 1
+**                                              Superblock version 0, 1, 2, 3
 **                  --------------------------------------------------------------------------------
 **                  | (earliest, v18) | (earliest, v110) | (v18, v18) | (v18, v110) | (v110, v110) |
 **                  |______________________________________________________________________________|
@@ -6261,26 +6248,6 @@ test_libver_bounds_super_create(hid_t fapl, hid_t fcpl, htri_t is_swmr, htri_t n
 **                  |______________________________________________________________________________|
 **
 **
-**                                              Superblock version 2
-**                  --------------------------------------------------------------------------------
-**                  | (earliest, v18) | (earliest, v110) | (v18, v18) | (v18, v110) | (v110, v110) |
-**                  |______________________________________________________________________________|
-** File's low bound |               -->v18               |               no change                 |
-**                  |------------------------------------------------------------------------------|
-** File open        |                               succeed                                        |
-**                  |______________________________________________________________________________|
-**
-**                                              Superblock version 3
-**                  --------------------------------------------------------------------------------
-**                  | (earliest, v18) | (earliest, v110) | (v18, v18) | (v18, v110) | (v110, v110) |
-**                  |______________________________________________________________________________|
-** File's low bound | --              | -->v110          | --         | -->v110     | no change    |
-**                  |------------------------------------------------------------------------------|
-** File open        | fail            | succeed          | fail       | succeed     | succeed      |
-**                  |______________________________________________________________________________|
-**
-**
-**
 **                     (B) Opening a file with SWMR-write access
 **
 **                                              Superblock version 0, 1, 2
@@ -6316,9 +6283,7 @@ static void
 test_libver_bounds_super_open(hid_t fapl, hid_t fcpl, htri_t is_swmr, htri_t non_def_fsm)
 {
     hid_t        fid      = H5I_INVALID_HID; /* File ID */
-    H5F_t       *f        = NULL;            /* Internal file pointer */
     hid_t        new_fapl = H5I_INVALID_HID; /* File access property list */
-    unsigned     super_vers;                 /* Superblock version */
     H5F_libver_t low, high;                  /* Low and high bounds */
     herr_t       ret;                        /* Return value */
 
@@ -6339,13 +6304,6 @@ test_libver_bounds_super_open(hid_t fapl, hid_t fcpl, htri_t is_swmr, htri_t non
     else {
         VERIFY(fid >= 0, true, "H5Fcreate");
 
-        /* Get the internal file pointer */
-        f = (H5F_t *)H5VL_object(fid);
-        CHECK_PTR(f, "H5VL_object");
-
-        /* The file's superblock version */
-        super_vers = f->shared->sblock->super_vers;
-
         /* Close the file */
         ret = H5Fclose(fid);
         CHECK(ret, FAIL, "H5Fclose");
@@ -6374,66 +6332,18 @@ test_libver_bounds_super_open(hid_t fapl, hid_t fcpl, htri_t is_swmr, htri_t non
                 }
                 H5E_END_TRY
 
-                if (non_def_fsm && high < H5F_LIBVER_V110) {
-                    VERIFY(fid, H5I_INVALID_HID, "H5Fopen");
-                    continue;
-                }
-
                 /* Get the internal file pointer if the open succeeds */
                 if (fid >= 0) {
-                    f = (H5F_t *)H5VL_object(fid);
-                    CHECK_PTR(f, "H5VL_object");
+                    ret = H5Fclose(fid);
+                    CHECK(ret, FAIL, "H5Fclose");
                 }
+                else {
 
-                /* Verify the file open succeeds or fails */
-                switch (super_vers) {
-                    case 3:
-                        if (high >= H5F_LIBVER_V110) {
-                            /* Should succeed */
-                            VERIFY(fid >= 0, true, "H5Fopen");
-                            VERIFY(f->shared->low_bound >= H5F_LIBVER_V110, true,
-                                   "HDF5_superblock_ver_bounds");
-
-                            /* Close the file */
-                            ret = H5Fclose(fid);
-                            CHECK(ret, FAIL, "H5Fclose");
-                        }
-                        else /* Should fail */
-                            VERIFY(fid >= 0, false, "H5Fopen");
-                        break;
-
-                    case 2:
-                        if (is_swmr) /* Should fail */
-                            VERIFY(fid >= 0, false, "H5Fopen");
-                        else { /* Should succeed */
-                            VERIFY(fid >= 0, true, "H5Fopen");
-                            VERIFY(f->shared->low_bound >= H5F_LIBVER_V18, true,
-                                   "HDF5_superblock_ver_bounds");
-
-                            /* Close the file */
-                            ret = H5Fclose(fid);
-                            CHECK(ret, FAIL, "H5Fclose");
-                        }
-                        break;
-
-                    case 1:
-                    case 0:
-                        if (is_swmr) /* Should fail */
-                            VERIFY(fid >= 0, false, "H5Fopen");
-                        else { /* Should succeed */
-                            VERIFY(fid >= 0, true, "H5Fopen");
-                            VERIFY(f->shared->low_bound, low, "HDF5_superblock_ver_bounds");
-
-                            ret = H5Fclose(fid);
-                            CHECK(ret, FAIL, "H5Fclose");
-                        }
-                        break;
+                    VERIFY((is_swmr || (non_def_fsm && (high < H5F_LIBVER_V110))), true, "H5Fopen");
+                }
 
-                    default:
-                        break;
-                } /* end switch */
-            }     /* end for */
-        }         /* end for */
+            } /* end for */
+        }     /* end for */
 
         /* Close the file access property list */
         ret = H5Pclose(new_fapl);
@@ -6555,6 +6465,7 @@ test_libver_bounds_obj(hid_t fapl)
                 fid = H5Fopen(FILE8, H5F_ACC_RDWR, new_fapl);
             }
             H5E_END_TRY
+            VERIFY((fid >= 0), true, "File open should succeed");
 
             if (fid >= 0) { /* The file open succeeds */
 
@@ -6773,6 +6684,7 @@ test_libver_bounds_dataset(hid_t fapl)
                 fid = H5Fopen(FILE8, H5F_ACC_RDWR, new_fapl);
             }
             H5E_END_TRY
+            VERIFY((fid >= 0), true, "File open should succeed");
 
             if (fid >= 0) { /* The file open succeeds */
 
@@ -7002,6 +6914,7 @@ test_libver_bounds_dataspace(hid_t fapl)
                 fid = H5Fopen(FILE8, H5F_ACC_RDWR, new_fapl);
             }
             H5E_END_TRY
+            VERIFY((fid >= 0), true, "File open should succeed");
 
             if (fid >= 0) { /* The file open succeeds */
 
@@ -7338,6 +7251,7 @@ test_libver_bounds_datatype_check(hid_t fapl, hid_t tid)
                 fid = H5Fopen(FILE8, H5F_ACC_RDWR, new_fapl);
             }
             H5E_END_TRY
+            VERIFY((fid >= 0), true, "File open should succeed");
 
             if (fid >= 0) { /* The file open succeeds */
 
@@ -7666,6 +7580,7 @@ test_libver_bounds_attributes(hid_t fapl)
                 fid = H5Fopen(FILE8, H5F_ACC_RDWR, new_fapl);
             }
             H5E_END_TRY
+            VERIFY((fid >= 0), true, "File open should succeed");
 
             if (fid >= 0) { /* The file open succeeds */
 
@@ -7686,7 +7601,7 @@ test_libver_bounds_attributes(hid_t fapl)
                 CHECK_PTR(attr, "H5VL_object");
 
                 /* Verify the attribute message version */
-                VERIFY(attr->shared->version, H5O_attr_ver_bounds[f->shared->low_bound],
+                VERIFY(attr->shared->version >= H5O_attr_ver_bounds[f->shared->low_bound], true,
                        "H5O_attr_ver_bounds");
 
                 /* Close the attribute */
diff --git a/test/tmisc.c b/test/tmisc.c
index 8c73aa61949..a368aa0fa96 100644
--- a/test/tmisc.c
+++ b/test/tmisc.c
@@ -6868,7 +6868,7 @@ test_misc40(void)
     CHECK(ret, FAIL, "H5Fclose");
 
     /* Re-open the file */
-    fid = H5Fopen(MISC25C_FILE, H5F_ACC_RDWR, H5P_DEFAULT);
+    fid = H5Fopen(MISC25C_FILE, H5F_ACC_RDWR, fapl);
     CHECK(fid, H5I_INVALID_HID, "H5Fopen");
 
     /* Set the compact/dense value high, to see if we can trick the