diff --git a/etc/config.csh/FFTW b/etc/config.csh/FFTW
index 5afe82d226..50d617511a 100644
--- a/etc/config.csh/FFTW
+++ b/etc/config.csh/FFTW
@@ -8,8 +8,7 @@
 #     Copyright (C) 2016-2018 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.csh/FFTW
diff --git a/etc/config.csh/complete-wrapper b/etc/config.csh/complete-wrapper
index c418f5020a..b080ae6727 100644
--- a/etc/config.csh/complete-wrapper
+++ b/etc/config.csh/complete-wrapper
@@ -9,8 +9,7 @@
 #     Copyright (C) 2017 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.csh/complete-wrapper
@@ -38,14 +37,14 @@ then
 fi
 
 # Preload completion cache
-if [ -f $WM_PROJECT_DIR/etc/config.sh/completion_cache ]
-then  . $WM_PROJECT_DIR/etc/config.sh/completion_cache
+if [ -f "$WM_PROJECT_DIR"/etc/config.sh/completion_cache ]
+then  . "$WM_PROJECT_DIR"/etc/config.sh/completion_cache
 fi
 
 # Use the bash completion function, but retain cache etc.
 _of_complete_tcsh=true
-if [ -f $WM_PROJECT_DIR/etc/config.sh/bash_completion ]
-then  . $WM_PROJECT_DIR/etc/config.sh/bash_completion
+if [ -f "$WM_PROJECT_DIR"/etc/config.sh/bash_completion ]
+then  . "$WM_PROJECT_DIR"/etc/config.sh/bash_completion
 else
     # Could warn about missing file, or treat silently
     echo
diff --git a/etc/config.csh/example/prefs.csh b/etc/config.csh/example/prefs.csh
index d4504c70b4..10d13da677 100644
--- a/etc/config.csh/example/prefs.csh
+++ b/etc/config.csh/example/prefs.csh
@@ -8,8 +8,7 @@
 #     Copyright (C) 2011-2016 OpenFOAM Foundation
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     config.csh/example/prefs.csh
diff --git a/etc/config.csh/mpi b/etc/config.csh/mpi
index 48126fde7a..e8bd71b0d4 100644
--- a/etc/config.csh/mpi
+++ b/etc/config.csh/mpi
@@ -40,7 +40,7 @@
 #
 # Environment
 #     I_MPI_CC, I_MPI_CXX environment variables define the compiler
-#     to be used the Intel mpicc/mpicxx wrappers
+#     to be used by Intel mpiicc/mpiicpc wrappers
 #
 #     MPI_BUFFER_SIZE overrides 'mpiBufferSize' (controlDict entry).
 #     Eg,  setenv MPI_BUFFER_SIZE 20000000
@@ -73,14 +73,57 @@ case SYSTEMOPENMPI:
     if ( -d "$MPI_ARCH_PATH" ) then
         _foamAddLibAuto "$MPI_ARCH_PATH"
     else
-        # Slight hack: strip off 'lib' to get prefix directory
-        set libDir=`mpicc --showme:link | sed -e 's/.*-L\([^ ]*\).*/\1/'`
-
-        setenv MPI_ARCH_PATH "${libDir:h}"  # prefix from libdir
-        _foamAddLib "$libDir"
-        unset libDir
+        setenv MPI_ARCH_PATH
     endif
 
+    # Use <orte-info> (openmpi only command) to query configuration
+    if ( "$MPI_ARCH_PATH" == "" ) then
+        set _foamFoundCmd=`which orte-info`
+        if ($status == 0) then
+            # prefix
+            set _foamFoundDir=`orte-info --path prefix --parsable | sed -e 's/^.*:prefix://'`
+            if ( -d "$_foamFoundDir" ) then
+                setenv MPI_ARCH_PATH "${_foamFoundDir}"
+
+                # libdir
+                set _foamFoundDir=`orte-info --path libdir --parsable | sed -e 's/^.*:libdir://'`
+                if ( -d "$_foamFoundDir" ) then
+                    _foamAddLib "$_foamFoundDir"
+                else if ( "$MPI_ARCH_PATH" != "/usr" ) then
+                    _foamAddLibAuto "$MPI_ARCH_PATH"
+                endif
+            endif
+        endif
+    endif
+
+    # Use <mpicc> to get the link information and (slight hack)
+    # strip off 'lib' to get the prefix directory
+    if ( "$MPI_ARCH_PATH" == "" ) then
+        set _foamFoundCmd=`which mpicc`
+        if ($status == 0) then
+            set _foamFoundDir=`mpicc --showme:link | sed -e 's/.*-L\([^ ]*\).*/\1/'`
+            setenv MPI_ARCH_PATH "${_foamFoundDir:h}"  # Prefix from libdir
+            _foamAddLib "$_foamFoundDir"
+        endif
+    endif
+
+    # Last resort (worse hack):
+    # Use <orterun> to get ../path/bin/orterun and infer prefix, libdir
+    if ( "$MPI_ARCH_PATH" == "" ) then
+        set _foamFoundCmd=`which orterun`
+        if ($status == 0) then
+            set _foamFoundDir="${_foamFoundCmd:h}"      # The bin dir
+            setenv MPI_ARCH_PATH "${_foamFoundDir:h}"   # The prefix dir
+
+            _foamAddLibAuto "$MPI_ARCH_PATH"
+        endif
+    endif
+
+    if ( "$MPI_ARCH_PATH" == "" ) then
+        echo "Warn: could not determine prefix for system-openmpi"
+    endif
+    unset _foamFoundCmd _foamFoundDir
+
     #-
     # TBD: extra (major) version qualifier on name?
     #-
@@ -107,9 +150,11 @@ case OPENMPI:
     # Inform openmpi where to find its install directory
     setenv OPAL_PREFIX "$MPI_ARCH_PATH"
 
-    _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddMan     "$MPI_ARCH_PATH"/share/man
-    _foamAddLibAuto "$MPI_ARCH_PATH"  "lib$WM_COMPILER_LIB_ARCH"
+    if ( "$MPI_ARCH_PATH" != "" ) then
+        _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddMan     "$MPI_ARCH_PATH"/share/man
+        _foamAddLibAuto "$MPI_ARCH_PATH"  "lib$WM_COMPILER_LIB_ARCH"
+    endif
     breaksw
 
 
@@ -179,10 +224,11 @@ case MPICH:
     endif
 
     setenv MPI_HOME "$MPI_ARCH_PATH"
-
-    _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddMan     "$MPI_ARCH_PATH"/share/man
-    _foamAddLibAuto "$MPI_ARCH_PATH"  "lib$WM_COMPILER_LIB_ARCH"
+    if ( "$MPI_ARCH_PATH" != "" ) then
+        _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddMan     "$MPI_ARCH_PATH"/share/man
+        _foamAddLibAuto "$MPI_ARCH_PATH"  "lib$WM_COMPILER_LIB_ARCH"
+    endif
     breaksw
 
 
@@ -198,9 +244,11 @@ case MPICH-GM:
     setenv MPICH_PATH "$MPI_ARCH_PATH"
     setenv GM_LIB_PATH "$MPICH_PATH/lib$WM_COMPILER_LIB_ARCH"
 
-    _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddLib     "$MPI_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH"
-    _foamAddLib     "$GM_LIB_PATH"
+    if ( "$MPI_ARCH_PATH" != "" ) then
+        _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddLib     "$MPI_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH"
+        _foamAddLib     "$GM_LIB_PATH"
+    endif
     breaksw
 
 
@@ -214,9 +262,11 @@ case MVA2MPI:
         setenv MPI_ARCH_PATH "$_foamMpiPrefixDir/$FOAM_MPI"
     endif
 
-    _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddMan     "$MPI_ARCH_PATH"/share/man
-    _foamAddLibAuto "$MPI_ARCH_PATH"  "lib$WM_COMPILER_LIB_ARCH"
+    if ( "$MPI_ARCH_PATH" != "" ) then
+        _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddMan     "$MPI_ARCH_PATH"/share/man
+        _foamAddLibAuto "$MPI_ARCH_PATH"  "lib$WM_COMPILER_LIB_ARCH"
+    endif
     breaksw
 
 
@@ -231,8 +281,10 @@ case CRAY-MPICH:
         echo "Please set MPICH_DIR correctly"
     endif
 
-    # _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddLib     "$MPI_ARCH_PATH"/lib
+    if ( "$MPI_ARCH_PATH" != "" ) then
+        # _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddLib     "$MPI_ARCH_PATH"/lib
+    endif
     breaksw
 
 
@@ -241,26 +293,26 @@ case HPMPI:
     setenv MPI_HOME /opt/hpmpi
     setenv MPI_ARCH_PATH "$MPI_HOME"
 
-    set libDir=""
+    set _foamFoundDir=""
     switch (`uname -m`)
     case x86_64:
-        set libDir=lib/linux_amd64
+        set _foamFoundDir=lib/linux_amd64
         breaksw
     case i686:
-        set libDir=lib/linux_ia32
+        set _foamFoundDir=lib/linux_ia32
         breaksw
     case ia64:
-        set libDir=lib/linux_ia64
+        set _foamFoundDir=lib/linux_ia64
         breaksw
     endsw
 
-    if ( "${libDir}" != "" ) then
+    if ( "${_foamFoundDir}" != "" ) then
         _foamAddPath "$MPI_ARCH_PATH"/bin
-        _foamAddLib  "$MPI_ARCH_PATH/$libDir"
+        _foamAddLib  "$MPI_ARCH_PATH/$_foamFoundDir"
     else
         echo "openfoam: (`uname -m`) - unsupported HP-MPI processor type"
     endif
-    unset libDir
+    unset _foamFoundDir
     breaksw
 
 
@@ -335,7 +387,20 @@ case INTELMPI*:
     else if ( "$MPI_ARCH_PATH" != "" ) then
         # MPI_ARCH_PATH: Set I_MPI_ROOT accordingly
         setenv I_MPI_ROOT "$MPI_ARCH_PATH"
+    else
+        # Final effort - check ThirdParty opt/intel locations for 'latest'
+        foreach _foamFoundDir (\
+            "$WM_THIRD_PARTY_DIR/opt/intel/oneapi/mpi/latest" \
+            "$WM_THIRD_PARTY_DIR/opt/intel/mpi/latest" \
+        )
+            if ( -d "$_foamFoundDir" ) then
+                setenv MPI_ARCH_PATH "$_foamFoundDir"
+                setenv I_MPI_ROOT "$MPI_ARCH_PATH"
+                break
+            endif
+        end
     endif
+    unset _foamFoundDir
 
     if ( -d "$MPI_ARCH_PATH" ) then
         # Remove trailing slash
@@ -364,7 +429,7 @@ case INTELMPI*:
     # With/without "intel64/" directory - handled here and in mpi rules
 
     # Path, lib-path may have been set prior to call
-    if (1) then
+    if ( -d "$MPI_ARCH_PATH" ) then
         if ( -d "$MPI_ARCH_PATH"/intel64/lib ) then
             _foamAddPath "$MPI_ARCH_PATH"/intel64/bin
             _foamAddLib "$MPI_ARCH_PATH"/intel64/lib
@@ -375,6 +440,34 @@ case INTELMPI*:
             _foamAddLib "$MPI_ARCH_PATH"/lib/release
         endif
     endif
+    breaksw
+
+
+case MSMPI:
+    setenv FOAM_MPI msmpi
+    _foamEtc -config prefs.msmpi  ## Optional adjustments
+
+    # MPI_ARCH_PATH (prefs) if a valid dir, or ThirdParty location
+    # Also consider ThirdParty 'opt/' directory (binary package)
+    if ( ! -d "$MPI_ARCH_PATH" ) then
+        foreach _foamFoundDir (\
+            "$_foamMpiPrefixDir/$FOAM_MPI" \
+            "$WM_THIRD_PARTY_DIR/opt/$FOAM_MPI" \
+        )
+            if ( -d "$_foamFoundDir" ) then
+                setenv MPI_ARCH_PATH "$_foamFoundDir"
+                break
+            endif
+        end
+    endif
+    unset _foamFoundDir
+
+    if ( -d "$MPI_ARCH_PATH" ) then
+        # _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddLib     "$MPI_ARCH_PATH"/lib/x64
+    endif
+    breaksw
+
 endsw
 
 
diff --git a/etc/config.csh/settings b/etc/config.csh/settings
index 4919f0092a..3c6bb87a56 100644
--- a/etc/config.csh/settings
+++ b/etc/config.csh/settings
@@ -96,7 +96,7 @@ case MSYS*:
     if ( "$WM_COMPILER" == Gcc ) setenv WM_COMPILER Mingw
     setenv WM_COMPILER_LIB_ARCH 64  # Consistent with linux64Mingw
     echo "openfoam: windows support (mingw64) is runtime only"
-    ;;
+    breaksw
 
 case SunOS*:
     setenv WM_ARCH solaris64
@@ -146,12 +146,12 @@ setenv FOAM_USER_APPBIN "$WM_PROJECT_USER_DIR/platforms/$WM_OPTIONS/bin"
 setenv FOAM_USER_LIBBIN "$WM_PROJECT_USER_DIR/platforms/$WM_OPTIONS/lib"
 
 # Prepend wmake to the path - not required for runtime-only environment
-set foundDir="${WM_PROJECT_DIR}/wmake"
+set _foamFoundDir="${WM_PROJECT_DIR}/wmake"
 if ( $?WM_DIR ) then
-    if ( -d "${WM_DIR}" ) set foundDir="${WM_DIR}"
+    if ( -d "${WM_DIR}" ) set _foamFoundDir="${WM_DIR}"
 endif
-if ( -d "$foundDir" ) then
-    setenv PATH "${foundDir}:${PATH}"
+if ( -d "$_foamFoundDir" ) then
+    setenv PATH "${_foamFoundDir}:${PATH}"
 else
     unsetenv WM_DIR
 endif
@@ -317,7 +317,7 @@ endsw
 
 # Cleanup
 # ~~~~~~~
-unset archDir siteDir foundDir archOption
+unset archOption archDir siteDir _foamFoundDir
 unset gcc_version gccDir
 unset gmp_version gmpDir  mpfr_version mpfrDir  mpc_version mpcDir
 unset clang_version clangDir
diff --git a/etc/config.csh/setup b/etc/config.csh/setup
index 49d5d4ad5d..52b5476bb6 100644
--- a/etc/config.csh/setup
+++ b/etc/config.csh/setup
@@ -30,7 +30,7 @@
 setenv FOAM_API `$WM_PROJECT_DIR/bin/foamEtcFile -show-api`
 
 # The installation parent directory
-set prefixDir="${WM_PROJECT_DIR:h}"
+set _foamPrefixDir="${WM_PROJECT_DIR:h}"
 
 # Load shell "functions" (actually aliases)
 source "$WM_PROJECT_DIR/etc/config.csh/functions"
@@ -52,16 +52,16 @@ if ( -e "$WM_PROJECT_DIR/ThirdParty" ) then
     setenv WM_THIRD_PARTY_DIR "$WM_PROJECT_DIR/ThirdParty"
 else
     _foamEcho "Locating ThirdParty directory"
-    foreach foundDir (\
-        "$prefixDir/ThirdParty-$WM_PROJECT_VERSION" \
-        "$prefixDir/ThirdParty-v$FOAM_API" \
-        "$prefixDir/ThirdParty-$FOAM_API" \
-        "$prefixDir/ThirdParty-common" \
+    foreach _foamFoundDir (\
+        "$_foamPrefixDir/ThirdParty-$WM_PROJECT_VERSION" \
+        "$_foamPrefixDir/ThirdParty-v$FOAM_API" \
+        "$_foamPrefixDir/ThirdParty-$FOAM_API" \
+        "$_foamPrefixDir/ThirdParty-common" \
     )
-        _foamEcho "... $foundDir"
-        if ( -d "$foundDir" ) then
-            if ( -f "$foundDir/Allwmake" || -d "$foundDir/platforms" ) then
-                setenv WM_THIRD_PARTY_DIR "$foundDir"
+        _foamEcho "... $_foamFoundDir"
+        if ( -d "$_foamFoundDir" ) then
+            if ( -f "$_foamFoundDir/Allwmake" || -d "$_foamFoundDir/platforms" ) then
+                setenv WM_THIRD_PARTY_DIR "$_foamFoundDir"
                 break
             else
                 _foamEcho "    does not have Allwmake or platforms/"
@@ -239,6 +239,6 @@ unalias _foamAddLib
 unalias _foamAddLibAuto
 
 # Variables (done as final statement for a clean exit code)
-unset cleaned foamOldDirs foundDir prefixDir
+unset cleaned foamOldDirs _foamFoundDir _foamPrefixDir
 
 #------------------------------------------------------------------------------
diff --git a/etc/config.csh/tcsh_completion b/etc/config.csh/tcsh_completion
index 8298359d4e..eb93432d4f 100644
--- a/etc/config.csh/tcsh_completion
+++ b/etc/config.csh/tcsh_completion
@@ -8,8 +8,7 @@
 #     Copyright (C) 2017 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.csh/tcsh_completion
diff --git a/etc/config.csh/vtk b/etc/config.csh/vtk
index 1a8c37cca6..0775b85d98 100644
--- a/etc/config.csh/vtk
+++ b/etc/config.csh/vtk
@@ -8,8 +8,7 @@
 #     Copyright (C) 2016-2019 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.csh/vtk
diff --git a/etc/config.sh/FFTW b/etc/config.sh/FFTW
index 65e1658187..ac39eeb010 100644
--- a/etc/config.sh/FFTW
+++ b/etc/config.sh/FFTW
@@ -8,8 +8,7 @@
 #     Copyright (C) 2016-2018 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.sh/FFTW
diff --git a/etc/config.sh/ccmio b/etc/config.sh/ccmio
index 122bd43f9e..7db620c46b 100644
--- a/etc/config.sh/ccmio
+++ b/etc/config.sh/ccmio
@@ -8,8 +8,7 @@
 #     Copyright (C) 2016 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.sh/ccmio
diff --git a/etc/config.sh/functions b/etc/config.sh/functions
index 5945ba8bde..1c9ee25bff 100644
--- a/etc/config.sh/functions
+++ b/etc/config.sh/functions
@@ -50,35 +50,31 @@ then
     if [ -n "$FOAM_VERBOSE" ] && [ -n "$PS1" ]
     then
         _foamEcho() { echo "$@" 1>&2; }
-        _foamEtc() {
-            eval "$("$WM_PROJECT_DIR"/bin/foamEtcFile -sh-verbose "$@")";
-        }
+        _foamEtc()  { eval "$("$WM_PROJECT_DIR"/bin/foamEtcFile -sh-verbose "$@")"; }
     else
         _foamEcho() { true; }
-        _foamEtc() {
-            eval "$("$WM_PROJECT_DIR"/bin/foamEtcFile -sh "$@")";
-        }
+        _foamEtc()  { eval "$("$WM_PROJECT_DIR"/bin/foamEtcFile -sh "$@")"; }
     fi
 
     # Prepend PATH
     unset -f _foamAddPath 2>/dev/null
     _foamAddPath()
     {
-        [ -n "$1" ] && export PATH="$1:$PATH"
+        case "$1" in (/?*) export PATH="$1:$PATH" ;; esac
     }
 
     # Prepend MANPATH
     unset -f _foamAddMan 2>/dev/null
     _foamAddMan()
     {
-        [ -n "$1" ] && export MANPATH="$1:$MANPATH"
+        case "$1" in (/?*) export MANPATH="$1:$MANPATH" ;; esac
     }
 
     # Prepend LD_LIBRARY_PATH
     unset -f _foamAddLib 2>/dev/null
     _foamAddLib()
     {
-        [ -n "$1" ] && export LD_LIBRARY_PATH="$1:$LD_LIBRARY_PATH"
+        case "$1" in (/?*) export LD_LIBRARY_PATH="$1:$LD_LIBRARY_PATH" ;; esac
     }
 
     # Prepend to LD_LIBRARY_PATH with additional checking
@@ -118,11 +114,11 @@ then
         fi
 
         # Use fallback. Add without checking existence of the directory
-        foamVar_end=$2
+        foamVar_end="$2"
         if [ -n "$foamVar_end" ]
         then
             case "$foamVar_end" in
-            /*)     # An absolute path
+            (/*)    # Absolute path
                 export LD_LIBRARY_PATH="$foamVar_end:$LD_LIBRARY_PATH"
                 ;;
             (*)     # Relative to prefix
@@ -147,7 +143,7 @@ then
         # Prepend DYLD_LIBRARY_PATH
         _foamAddLib()
         {
-            [ -n "$1" ] && export DYLD_LIBRARY_PATH="$1:$DYLD_LIBRARY_PATH"
+            case "$1" in (/?*) export DYLD_LIBRARY_PATH="$1:$DYLD_LIBRARY_PATH" ;; esac
         }
 
         # Prepend to DYLD_LIBRARY_PATH with additional checking
diff --git a/etc/config.sh/kahip b/etc/config.sh/kahip
index 6eb3854759..cada0abc78 100644
--- a/etc/config.sh/kahip
+++ b/etc/config.sh/kahip
@@ -8,8 +8,7 @@
 #     Copyright (C) 2017-2019 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.sh/kahip
diff --git a/etc/config.sh/metis b/etc/config.sh/metis
index ce42f62a5f..6242dda174 100644
--- a/etc/config.sh/metis
+++ b/etc/config.sh/metis
@@ -9,8 +9,7 @@
 #     Copyright (C) 2016-2017 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.sh/metis
diff --git a/etc/config.sh/mgridgen b/etc/config.sh/mgridgen
index 3ef0ce4acb..52a77782b2 100644
--- a/etc/config.sh/mgridgen
+++ b/etc/config.sh/mgridgen
@@ -8,8 +8,7 @@
 #     Copyright (C) 2017 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.sh/mgridgen
diff --git a/etc/config.sh/mpi b/etc/config.sh/mpi
index ed38419271..d131891f9c 100644
--- a/etc/config.sh/mpi
+++ b/etc/config.sh/mpi
@@ -38,7 +38,7 @@
 #
 # Environment
 #     I_MPI_CC, I_MPI_CXX environment variables define the compiler
-#     to be used the Intel mpicc/mpicxx wrappers
+#     to be used by Intel mpiicc/mpiicpc wrappers
 #
 #     MPI_BUFFER_SIZE overrides 'mpiBufferSize' (controlDict entry).
 #     Eg,  export MPI_BUFFER_SIZE=20000000
@@ -71,19 +71,63 @@ SYSTEMOPENMPI | SYSTEMOPENMPI[1-9])
     fi
     _foamEtc -config prefs.sys-openmpi  ## Optional adjustments
 
-    # MPI_ARCH_PATH (prefs) if a valid dir, or discover via <mpicc>
+    unset _foamFoundCmd
+
+    # MPI_ARCH_PATH (prefs) if a valid dir, or need to discover
     if [ -d "$MPI_ARCH_PATH" ]
     then
         _foamAddLibAuto "$MPI_ARCH_PATH"
     else
-        # Slight hack: strip off 'lib' to get prefix directory
-        libDir=$(mpicc --showme:link | sed -e 's/.*-L\([^ ]*\).*/\1/')
-
-        export MPI_ARCH_PATH="${libDir%/*}"  # prefix from libdir
-        _foamAddLib "$libDir"
-        unset libDir
+        unset MPI_ARCH_PATH
     fi
 
+    # Use <orte-info> (openmpi only command) to query configuration
+    if [ -z "$MPI_ARCH_PATH" ] && _foamFoundCmd="$(command -v orte-info)"
+    then
+        # prefix
+        _foamFoundDir="$("$_foamFoundCmd" --path prefix --parsable | sed -e 's/^.*:prefix://')"
+        if [ -d "$_foamFoundDir" ]
+        then
+            MPI_ARCH_PATH="${_foamFoundDir}"
+
+            # libdir
+            _foamFoundDir="$("$_foamFoundCmd" --path libdir --parsable | sed -e 's/^.*:libdir://')"
+            if [ -d "$_foamFoundDir" ]
+            then
+                _foamAddLib "$_foamFoundDir"
+            elif [ "$MPI_ARCH_PATH" != /usr ]
+            then
+                _foamAddLibAuto "$MPI_ARCH_PATH"
+            fi
+        fi
+    fi
+
+    # Use <mpicc> to get the link information and (slight hack)
+    # strip off 'lib' to get the prefix directory
+    if [ -z "$MPI_ARCH_PATH" ] && _foamFoundCmd="$(command -v mpicc)"
+    then
+        _foamFoundDir="$("$_foamFoundCmd" --showme:link | sed -e 's/.*-L\([^ ]*\).*/\1/')"
+
+        MPI_ARCH_PATH="${_foamFoundDir%/*}"  # Prefix from libdir
+        _foamAddLib "$_foamFoundDir"
+    fi
+
+    # Last resort (worse hack):
+    # Use <orterun> to get ../path/bin/orterun and infer prefix, libdir
+    if [ -z "$MPI_ARCH_PATH" ] && _foamFoundCmd="$(command -v orterun)"
+    then
+        _foamFoundDir="${_foamFoundCmd%/*}"  # The bin dir
+        MPI_ARCH_PATH="${_foamFoundDir%/*}"  # The prefix dir
+
+        _foamAddLibAuto "$MPI_ARCH_PATH"
+    fi
+
+    if [ -z "$MPI_ARCH_PATH" ]
+    then
+        echo "Warn: could not determine prefix for system-openmpi" 1>&2
+    fi
+    unset _foamFoundCmd _foamFoundDir
+
     #-
     # TBD: extra (major) version qualifier on name?
     #-
@@ -113,7 +157,7 @@ OPENMPI)
     export OPAL_PREFIX="$MPI_ARCH_PATH"
 
     # Could be sourced from ThirdParty with incomplete environment
-    if command -v _foamAddLibAuto >/dev/null  # Normal sourcing
+    if [ -n "$MPI_ARCH_PATH" ] && command -v _foamAddLibAuto >/dev/null
     then
         _foamAddPath    "$MPI_ARCH_PATH"/bin
         _foamAddMan     "$MPI_ARCH_PATH"/share/man
@@ -197,7 +241,7 @@ MPICH)
     export MPI_HOME="$MPI_ARCH_PATH"
 
     # Could be sourced from ThirdParty with incomplete environment
-    if command -v _foamAddLibAuto >/dev/null  # Normal sourcing
+    if [ -n "$MPI_ARCH_PATH" ] && command -v _foamAddLibAuto >/dev/null
     then
         _foamAddPath    "$MPI_ARCH_PATH"/bin
         _foamAddMan     "$MPI_ARCH_PATH"/share/man
@@ -219,9 +263,12 @@ MPICH-GM)
     export MPICH_PATH="$MPI_ARCH_PATH"
     export GM_LIB_PATH="$MPICH_PATH/lib$WM_COMPILER_LIB_ARCH"
 
-    _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddLib     "$MPI_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH"
-    _foamAddLib     "$GM_LIB_PATH"
+    if [ -n "$MPI_ARCH_PATH" ]
+    then
+        _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddLib     "$MPI_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH"
+        _foamAddLib     "$GM_LIB_PATH"
+    fi
     ;;
 
 
@@ -237,7 +284,7 @@ MVA2MPI)
     fi
 
     # Could be sourced from ThirdParty with incomplete environment
-    if command -v _foamAddLibAuto >/dev/null  # Normal sourcing
+    if [ -n "$MPI_ARCH_PATH" ] && command -v _foamAddLibAuto >/dev/null
     then
         _foamAddPath    "$MPI_ARCH_PATH"/bin
         _foamAddMan     "$MPI_ARCH_PATH"/share/man
@@ -256,8 +303,11 @@ CRAY-MPICH)
         echo "Please set MPICH_DIR correctly" 1>&2
     }
 
-    # _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddLib     "$MPI_ARCH_PATH"/lib
+    if [ -n "$MPI_ARCH_PATH" ]
+    then
+        # _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddLib     "$MPI_ARCH_PATH"/lib
+    fi
     ;;
 
 
@@ -266,21 +316,21 @@ HPMPI)
     export MPI_HOME=/opt/hpmpi
     export MPI_ARCH_PATH="$MPI_HOME"
 
-    unset libDir
     case "$(uname -m)" in
-    x86_64) libDir=lib/linux_amd64 ;;
-    i686)   libDir=lib/linux_ia32 ;;
-    ia64)   libDir=lib/linux_ia64 ;;
+    x86_64) _foamFoundDir=lib/linux_amd64 ;;
+    i686)   _foamFoundDir=lib/linux_ia32 ;;
+    ia64)   _foamFoundDir=lib/linux_ia64 ;;
+    *)      unset _foamFoundDir ;;
     esac
 
-    if [ -n "$libDir" ]
+    if [ -n "$_foamFoundDir" ]
     then
         _foamAddPath "$MPI_ARCH_PATH"/bin
-        _foamAddLib  "$MPI_ARCH_PATH/$libDir"
+        _foamAddLib  "$MPI_ARCH_PATH/$_foamFoundDir"
     else
         echo "openfoam: ($(uname -m)) - unsupported HP-MPI processor type" 1>&2
     fi
-    unset libDir
+    unset _foamFoundDir
     ;;
 
 
@@ -361,8 +411,23 @@ INTELMPI*)
     then
         # MPI_ARCH_PATH: Set I_MPI_ROOT accordingly
         export I_MPI_ROOT="$MPI_ARCH_PATH"
-    fi
 
+    else
+        # Final effort - check ThirdParty opt/intel locations for 'latest'
+        for _foamFoundDir in \
+            "$WM_THIRD_PARTY_DIR/opt/intel/oneapi/mpi/latest" \
+            "$WM_THIRD_PARTY_DIR/opt/intel/mpi/latest" \
+        ;
+        do
+            if [ -d "$_foamFoundDir" ]
+            then
+                MPI_ARCH_PATH="$_foamFoundDir"
+                export I_MPI_ROOT="$MPI_ARCH_PATH"
+                break
+            fi
+        done
+    fi
+    unset _foamFoundDir
 
     if [ -d "$MPI_ARCH_PATH" ]
     then
@@ -391,7 +456,7 @@ INTELMPI*)
     # With/without "intel64/" directory - handled here and in mpi rules
 
     # Path, lib-path may have been set prior to call
-    if true
+    if [ -d "$MPI_ARCH_PATH" ]
     then
         if [ -d "$MPI_ARCH_PATH"/intel64/bin ] \
         && [ -d "$MPI_ARCH_PATH"/intel64/lib ]
@@ -416,13 +481,28 @@ MSMPI)
     _foamEtc -config prefs.msmpi  ## Optional adjustments
 
     # MPI_ARCH_PATH (prefs) if a valid dir, or ThirdParty location
+    # Also consider ThirdParty 'opt/' directory (binary package)
     if [ ! -d "$MPI_ARCH_PATH" ]
     then
-        export MPI_ARCH_PATH="$_foamMpiPrefixDir/$FOAM_MPI"
+        for _foamFoundDir in \
+            "$_foamMpiPrefixDir/$FOAM_MPI" \
+            "$WM_THIRD_PARTY_DIR/opt/$FOAM_MPI" \
+        ;
+        do
+            if [ -d "$_foamFoundDir" ]
+            then
+                MPI_ARCH_PATH="$_foamFoundDir"
+                break
+            fi
+        done
     fi
+    unset _foamFoundDir
 
-    # _foamAddPath    "$MPI_ARCH_PATH"/bin
-    _foamAddLib     "$MPI_ARCH_PATH"/lib/x64
+    if [ -d "$MPI_ARCH_PATH" ]
+    then
+        # _foamAddPath    "$MPI_ARCH_PATH"/bin
+        _foamAddLib     "$MPI_ARCH_PATH"/lib/x64
+    fi
     ;;
 
 esac
diff --git a/etc/config.sh/settings b/etc/config.sh/settings
index 7a69e91e52..e27a2bf16e 100644
--- a/etc/config.sh/settings
+++ b/etc/config.sh/settings
@@ -143,14 +143,14 @@ export FOAM_USER_LIBBIN="$WM_PROJECT_USER_DIR/platforms/$WM_OPTIONS/lib"
 
 
 # Prepend wmake to the path - not required for runtime-only environment
-foundDir="$WM_PROJECT_DIR/wmake"
+_foamFoundDir="$WM_PROJECT_DIR/wmake"
 if [ -d "$WM_DIR" ]
 then
-    foundDir="${WM_DIR}"
+    _foamFoundDir="${WM_DIR}"
 fi
-if [ -d "$foundDir" ]
+if [ -d "$_foamFoundDir" ]
 then
-    PATH="$foundDir:$PATH"
+    PATH="$_foamFoundDir:$PATH"
 else
     unset WM_DIR
 fi
@@ -308,7 +308,7 @@ esac
 
 # Cleanup
 # ~~~~~~~
-unset archDir siteDir foundDir archOption
+unset archOption archDir siteDir _foamFoundDir
 unset gcc_version gccDir
 unset gmp_version gmpDir  mpfr_version mpfrDir  mpc_version mpcDir
 unset clang_version clangDir
diff --git a/etc/config.sh/setup b/etc/config.sh/setup
index 36ef8d63e9..fb0a1f5e59 100644
--- a/etc/config.sh/setup
+++ b/etc/config.sh/setup
@@ -30,7 +30,7 @@
 export FOAM_API=$("$WM_PROJECT_DIR/bin/foamEtcFile" -show-api)
 
 # The installation parent directory
-prefixDir="${WM_PROJECT_DIR%/*}"
+_foamPrefixDir="${WM_PROJECT_DIR%/*}"
 
 # Load shell functions
 unset WM_SHELL_FUNCTIONS
@@ -54,20 +54,20 @@ then
     WM_THIRD_PARTY_DIR="$WM_PROJECT_DIR/ThirdParty"
 else
     _foamEcho "Locating ThirdParty directory"
-    for foundDir in \
-        "$prefixDir/ThirdParty-$WM_PROJECT_VERSION" \
-        "$prefixDir/ThirdParty-v$FOAM_API" \
-        "$prefixDir/ThirdParty-$FOAM_API" \
-        "$prefixDir/ThirdParty-common" \
+    for _foamFoundDir in \
+        "$_foamPrefixDir/ThirdParty-$WM_PROJECT_VERSION" \
+        "$_foamPrefixDir/ThirdParty-v$FOAM_API" \
+        "$_foamPrefixDir/ThirdParty-$FOAM_API" \
+        "$_foamPrefixDir/ThirdParty-common" \
         ;
     do
-        _foamEcho "... $foundDir"
-        if [ -d "$foundDir" ]
+        _foamEcho "... $_foamFoundDir"
+        if [ -d "$_foamFoundDir" ]
         then
-            if [ -f "$foundDir/Allwmake" ] || \
-               [ -d "$foundDir/platforms" ]
+            if [ -f "$_foamFoundDir/Allwmake" ] || \
+               [ -d "$_foamFoundDir/platforms" ]
             then
-                WM_THIRD_PARTY_DIR="$foundDir"
+                WM_THIRD_PARTY_DIR="$_foamFoundDir"
                 break
             else
                 _foamEcho "    does not have Allwmake or platforms/"
@@ -259,6 +259,6 @@ fi
 . "$WM_PROJECT_DIR/etc/config.sh/functions"
 
 # Variables (done as the last statement for a clean exit code)
-unset cleaned foamOldDirs foundDir prefixDir
+unset cleaned foamOldDirs _foamFoundDir _foamPrefixDir
 
 #------------------------------------------------------------------------------
diff --git a/etc/config.sh/vtk b/etc/config.sh/vtk
index 312034f80e..3bc8c48402 100644
--- a/etc/config.sh/vtk
+++ b/etc/config.sh/vtk
@@ -8,8 +8,7 @@
 #     Copyright (C) 2016-2019 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     etc/config.sh/vtk