diff --git a/applications/utilities/mesh/manipulation/renumberMesh/Allwmake b/applications/utilities/mesh/manipulation/renumberMesh/Allwmake
index ee135cc373..8fbaba1674 100755
--- a/applications/utilities/mesh/manipulation/renumberMesh/Allwmake
+++ b/applications/utilities/mesh/manipulation/renumberMesh/Allwmake
@@ -13,11 +13,11 @@ then
     export LINK_FLAGS="${LINK_FLAGS} -lSloanRenumber"
 fi
 
-if [ -f "${ZOLTAN_ARCH_PATH}/lib/libzoltan.a" -a -f "${FOAM_LIBBIN}/libzoltanRenumber.so" ]
+if [ -f "${ZOLTAN_ARCH_PATH}/lib64/libzoltan.a" -a -f "${FOAM_LIBBIN}/libzoltanRenumber.so" ]
 then
     echo "Found libzoltanRenumber.so  --  enabling zoltan renumbering support."
     export COMPILE_FLAGS="-DFOAM_USE_ZOLTAN"
-    export LINK_FLAGS="${LINK_FLAGS} -lzoltanRenumber -L${ZOLTAN_ARCH_PATH}/lib -lzoltan"
+    export LINK_FLAGS="${LINK_FLAGS} -lzoltanRenumber -L${ZOLTAN_ARCH_PATH}/lib64 -lzoltan"
 fi
 
 wmake $targetType
diff --git a/src/renumber/zoltanRenumber/zoltanRenumber.C b/src/renumber/zoltanRenumber/zoltanRenumber.C
index 45aea6b156..ab3138d79a 100644
--- a/src/renumber/zoltanRenumber/zoltanRenumber.C
+++ b/src/renumber/zoltanRenumber/zoltanRenumber.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2019 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -21,31 +21,6 @@ License
     You should have received a copy of the GNU General Public License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
-Class
-    Foam::zoltanRenumber
-
-Description
-    Renumber using Zoltan
-
-    Zoltan install:
-    - in your ~/.bashrc:
-            export ZOLTAN_ARCH_DIR=\
-                $WM_THIRD_PARTY_DIR/platforms/linux64Gcc/Zoltan_XXX
-    - unpack into $WM_THIRD_PARTY_DIR
-    - cd Zoltan_XXX
-    - mkdir build
-    - cd build
-    - export CCFLAGS="-fPIC"
-    - export CXXFLAGS="-fPIC"
-    - export CFLAGS="-fPIC"
-    - export LDFLAGS="-shared"
-    - ../configure \
-        --prefix=$ZOLTAN_ARCH_DIR \
-        --with-ccflags=-fPIC --with-cxxflags=-fPIC --with-ldflags=-shared
-
-SourceFiles
-    zoltanRenumber.C
-
 \*---------------------------------------------------------------------------*/
 
 #include "zoltanRenumber.H"
@@ -59,7 +34,6 @@ SourceFiles
 #include "PstreamGlobals.H"
 
 #include "zoltan.h"
-#include <mpi.h>
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -79,58 +53,76 @@ namespace Foam
 static int get_number_of_vertices(void *data, int *ierr)
 {
     const Foam::polyMesh& mesh = *static_cast<const Foam::polyMesh*>(data);
+
     *ierr = ZOLTAN_OK;
+
     return mesh.nCells();
 }
 
 
-static void get_vertex_list(void *data, int sizeGID, int sizeLID,
-            ZOLTAN_ID_PTR globalID, ZOLTAN_ID_PTR localID,
-                  int wgt_dim, float *obj_wgts, int *ierr)
+static void get_vertex_list
+(
+    void* data,
+    int nGID,
+    int nLID,
+    ZOLTAN_ID_PTR globalIDs,
+    ZOLTAN_ID_PTR localIDs,
+    int wgt_dim,
+    float* obj_wgts,
+    int* ierr
+)
 {
     const Foam::polyMesh& mesh = *static_cast<const Foam::polyMesh*>(data);
 
-    *ierr = ZOLTAN_OK;
+    // In this example, return the IDs of our vertices, but no weights.
+    // Zoltan will assume equally weighted vertices.
 
-  /* In this example, return the IDs of our vertices, but no weights.
-   * Zoltan will assume equally weighted vertices.
-   */
-
-    wgt_dim = 0;
-    obj_wgts = nullptr;
+    // Global calculation engine
+    Foam::globalIndex globalCellMap(mesh.nCells());
 
     for (Foam::label i=0; i<mesh.nCells(); i++)
     {
-        globalID[i] = i;        // should be global
-        localID[i] = i;
+        localIDs[i] = i;
+        globalIDs[i] = globalCellMap.toGlobal(i);
     }
+
+    *ierr = ZOLTAN_OK;
 }
 
 
-static void get_num_edges_list(void *data, int sizeGID, int sizeLID,
-                      int num_obj,
-             ZOLTAN_ID_PTR globalID, ZOLTAN_ID_PTR localID,
-             int *numEdges, int *ierr)
+static void get_num_edges_list
+(
+    void* data,
+    int nGID,
+    int nLID,
+    int nCells,
+    ZOLTAN_ID_PTR globalIDs,
+    ZOLTAN_ID_PTR localIDs,
+    int* numEdges,
+    int* ierr
+)
 {
   const Foam::polyMesh& mesh = *static_cast<const Foam::polyMesh*>(data);
 
-    if ((sizeGID != 1) || (sizeLID != 1) || (num_obj != mesh.nCells()))
+    if ((nGID != 1) || (nLID != 1) || (nCells != mesh.nCells()))
     {
         *ierr = ZOLTAN_FATAL;
         return;
     }
 
-    for (Foam::label i=0; i < num_obj ;i++)
+    for (Foam::label i=0; i<nCells; i++)
     {
-        Foam::label celli = localID[i];
-        const Foam::cell& cFaces = mesh.cells()[celli];
+        const Foam::cell& cFaces = mesh.cells()[localIDs[i]];
+
         forAll(cFaces, cFacei)
         {
             Foam::label n = 0;
+
             if (mesh.isInternalFace(cFaces[cFacei]))
             {
                 n++;
             }
+
             numEdges[i] = n;
         }
     }
@@ -139,19 +131,29 @@ static void get_num_edges_list(void *data, int sizeGID, int sizeLID,
 }
 
 
-static void get_edge_list(void *data, int sizeGID, int sizeLID,
-        int num_obj, ZOLTAN_ID_PTR globalID, ZOLTAN_ID_PTR localID,
-        int *num_edges,
-        ZOLTAN_ID_PTR nborGID, int *nborProc,
-        int wgt_dim, float *ewgts, int *ierr)
+static void get_edge_list
+(
+    void* data,
+    int nGID,
+    int nLID,
+    int nCells,
+    ZOLTAN_ID_PTR globalIDs,
+    ZOLTAN_ID_PTR localIDs,
+    int* num_edges,
+    ZOLTAN_ID_PTR nborGID,
+    int* nborProc,
+    int wgt_dim,
+    float* ewgts,
+    int* ierr
+)
 {
     const Foam::polyMesh& mesh = *static_cast<const Foam::polyMesh*>(data);
 
     if
     (
-        (sizeGID != 1)
-     || (sizeLID != 1)
-     || (num_obj != mesh.nCells())
+        (nGID != 1)
+     || (nLID != 1)
+     || (nCells != mesh.nCells())
      || (wgt_dim != 1)
     )
     {
@@ -163,19 +165,21 @@ static void get_edge_list(void *data, int sizeGID, int sizeLID,
     int* nextProc = nborProc;
     float* nextWgt = ewgts;
 
-    for (Foam::label i=0; i < num_obj; i++)
+    for (Foam::label i=0; i < nCells; i++)
     {
-        Foam::label celli = localID[i];
-
+        const Foam::label celli = localIDs[i];
         const Foam::cell& cFaces = mesh.cells()[celli];
+
         forAll(cFaces, cFacei)
         {
             Foam::label n = 0;
 
-            Foam::label facei = cFaces[cFacei];
+            const Foam::label facei = cFaces[cFacei];
+
             if (mesh.isInternalFace(facei))
             {
                 Foam::label nbr = mesh.faceOwner()[facei];
+
                 if (nbr == celli)
                 {
                     nbr = mesh.faceNeighbour()[facei];
@@ -188,6 +192,7 @@ static void get_edge_list(void *data, int sizeGID, int sizeLID,
 
                 n++;
             }
+
             if (n != num_edges[i])
             {
                 *ierr = ZOLTAN_FATAL;
@@ -195,11 +200,12 @@ static void get_edge_list(void *data, int sizeGID, int sizeLID,
             }
         }
     }
+
     *ierr = ZOLTAN_OK;
 }
 
 
-static int get_mesh_dim(void *data, int *ierr)
+static int get_mesh_dim(void* data, int* ierr)
 {
     const Foam::polyMesh& mesh = *static_cast<const Foam::polyMesh*>(data);
 
@@ -209,43 +215,41 @@ static int get_mesh_dim(void *data, int *ierr)
 
 static void get_geom_list
 (
-    void *data,
-    int num_gid_entries,
-    int num_lid_entries,
-    int num_obj,
-    ZOLTAN_ID_PTR global_ids,
-    ZOLTAN_ID_PTR local_ids,
-    int num_dim,
-    double *geom_vec,
-    int *ierr
+    void* data,
+    int nGID,
+    int nLID,
+    int nCells,
+    ZOLTAN_ID_PTR globalIDs,
+    ZOLTAN_ID_PTR localIDs,
+    int nDim,
+    double* cellCentres,
+    int* ierr
 )
 {
     const Foam::polyMesh& mesh = *static_cast<const Foam::polyMesh*>(data);
 
     if
     (
-        (num_gid_entries != 1)
-     || (num_lid_entries != 1)
-     || (num_obj != mesh.nCells())
-     || (num_dim != mesh.nSolutionD())
+        (nGID != 1)
+     || (nLID != 1)
+     || (nCells != mesh.nCells())
+     || (nDim != mesh.nSolutionD())
     )
     {
         *ierr = ZOLTAN_FATAL;
         return;
     }
 
-    double* p = geom_vec;
-
+    double* p = cellCentres;
 
     const Foam::Vector<Foam::label>& sol = mesh.solutionD();
-
     const Foam::pointField& cc = mesh.cellCentres();
 
-    for (Foam::label celli = 0; celli < num_obj; celli++)
+    for (Foam::label celli=0; celli<nCells; celli++)
     {
         const Foam::point& pt = cc[celli];
 
-        for (Foam::direction cmpt = 0; cmpt < Foam::vector::nComponents; cmpt++)
+        for (Foam::direction cmpt=0; cmpt<Foam::vector::nComponents; cmpt++)
         {
             if (sol[cmpt] == 1)
             {
@@ -253,6 +257,7 @@ static void get_geom_list
             }
         }
     }
+
     *ierr = ZOLTAN_OK;
 }
 
@@ -270,7 +275,7 @@ Foam::zoltanRenumber::zoltanRenumber(const dictionary& renumberDict)
 
 Foam::labelList Foam::zoltanRenumber::renumber
 (
-    const polyMesh& pMesh,
+    const polyMesh& mesh,
     const pointField& points
 ) const
 {
@@ -287,8 +292,6 @@ Foam::labelList Foam::zoltanRenumber::renumber
     float ver;
     int rc = Zoltan_Initialize(argc, argv, &ver);
 
-    Foam::Pout<< "Initialised to " << ver << Foam::endl;
-
     if (rc != ZOLTAN_OK)
     {
         FatalErrorInFunction
@@ -297,76 +300,83 @@ Foam::labelList Foam::zoltanRenumber::renumber
 
     struct Zoltan_Struct *zz = Zoltan_Create(PstreamGlobals::MPI_COMM_FOAM);
 
-    polyMesh& mesh = const_cast<polyMesh&>(pMesh);
-
-
-    forAllConstIter(IDLList<entry>, coeffsDict_, iter)
     {
-        if (!iter().isDict())
+        forAllConstIter(IDLList<entry>, coeffsDict_, iter)
         {
-            const word& key = iter().keyword();
-            const word value(iter().stream());
+            if (!iter().isDict())
+            {
+                const word& key = iter().keyword();
+                const word value(iter().stream());
 
-            Info<< typeName << " : setting parameter " << key
-                << " to " << value << endl;
+                Info<< typeName << " : setting parameter " << key
+                    << " to " << value << endl;
 
-            Zoltan_Set_Param(zz, key.c_str(), value.c_str());
+                Zoltan_Set_Param(zz, key.c_str(), value.c_str());
+            }
         }
+
+        void* meshPtr = &const_cast<polyMesh&>(mesh);
+
+        Zoltan_Set_Param(zz, "ORDER_TYPE", "LOCAL");
+
+        Zoltan_Set_Num_Obj_Fn(zz, get_number_of_vertices, meshPtr);
+        Zoltan_Set_Obj_List_Fn(zz, get_vertex_list, meshPtr);
+
+        // Callbacks for geometry
+        Zoltan_Set_Num_Geom_Fn(zz, get_mesh_dim, meshPtr);
+        Zoltan_Set_Geom_Multi_Fn(zz, get_geom_list, meshPtr);
+
+        // Callbacks for connectivity
+        Zoltan_Set_Num_Edges_Multi_Fn(zz, get_num_edges_list, meshPtr);
+        Zoltan_Set_Edge_List_Multi_Fn(zz, get_edge_list, meshPtr);
     }
 
+    // Local to global cell index mapper
+    globalIndex globalCellMap(mesh.nCells());
 
-    Zoltan_Set_Num_Obj_Fn(zz, get_number_of_vertices, &mesh);
-    Zoltan_Set_Obj_List_Fn(zz, get_vertex_list, &mesh);
-
-    // Callbacks for geometry
-    Zoltan_Set_Num_Geom_Fn(zz, get_mesh_dim, &mesh);
-    Zoltan_Set_Geom_Multi_Fn(zz, get_geom_list, &mesh);
-
-    // Callbacks for connectivity
-    Zoltan_Set_Num_Edges_Multi_Fn(zz, get_num_edges_list, &mesh);
-    Zoltan_Set_Edge_List_Multi_Fn(zz, get_edge_list, &mesh);
-
-
-
-    // Note: !global indices
-    List<ZOLTAN_ID_TYPE> wantedCells(mesh.nCells());
-
-    globalIndex globalCells(mesh.nCells());
-    forAll(wantedCells, i)
+    List<ZOLTAN_ID_TYPE> globalCells(mesh.nCells());
+    forAll(globalCells, i)
     {
-        // wantedCells[i] = i;
-        wantedCells[i] = globalCells.toGlobal(i);
+        globalCells[i] = globalCellMap.toGlobal(i);
     }
 
+    // Old local to new global cell index map
+    // Values set by Zoltan_Order
     List<ZOLTAN_ID_TYPE> oldToNew(mesh.nCells());
 
+    // Call Zoltan to reorder the cells
     int err = Zoltan_Order
     (
         zz,
-        1,                                // int num_gid_entries,
-        mesh.globalData().nTotalCells(),  // int num_obj,
-        wantedCells.begin(),
+        1,              // int nGID,
+        mesh.nCells(),
+        globalCells.begin(),
         oldToNew.begin()
     );
 
+    // Check for Zoltan errors
     if (err != ZOLTAN_OK)
     {
         FatalErrorInFunction
             << "Failed Zoltan_Order" << exit(FatalError);
     }
 
-
+    // Free the argv array
     for (label i = 0; i < argc; i++)
     {
         free(argv[i]);
     }
 
+    // Free the Zoltan_Struct allocated by Zoltan_Create
+    Zoltan_Destroy(&zz);
 
+    // Map the oldToNew global cell indices to local
     labelList order(oldToNew.size());
     forAll(order, i)
     {
-        order[i] = oldToNew[i];
+        order[i] = globalCellMap.toLocal(oldToNew[i]);
     }
+
     return order;
 }
 
diff --git a/src/renumber/zoltanRenumber/zoltanRenumber.H b/src/renumber/zoltanRenumber/zoltanRenumber.H
index 533813a01b..3f23995a0b 100644
--- a/src/renumber/zoltanRenumber/zoltanRenumber.H
+++ b/src/renumber/zoltanRenumber/zoltanRenumber.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -25,7 +25,26 @@ Class
     Foam::zoltanRenumber
 
 Description
-    Use Zoltan
+    Use Zoltan for renumbering a case in parallel.
+
+    Note: Zoltan methods do not support serial operation.
+
+    Zoltan install:
+    - in your ~/.bashrc:
+            export ZOLTAN_ARCH_PATH=\
+                $WM_THIRD_PARTY_DIR/platforms/linux64Gcc/Zoltan_XXX
+    - unpack into $WM_THIRD_PARTY_DIR
+    - cd Zoltan_XXX
+    - mkdir build
+    - cd build
+    - export CCFLAGS="-fPIC"
+    - export CXXFLAGS="-fPIC"
+    - export CFLAGS="-fPIC"
+    - ../configure \
+        --prefix=$ZOLTAN_ARCH_DIR \
+        --with-ccflags=-fPIC --with-cxxflags=-fPIC
+    - make everything
+    - make install
 
 SourceFiles
     zoltanRenumber.C