diff --git a/applications/test/parallel-comm0/Test-parallel-comm0.C b/applications/test/parallel-comm0/Test-parallel-comm0.C
index dc6fdb064f..3abb70d6ba 100644
--- a/applications/test/parallel-comm0/Test-parallel-comm0.C
+++ b/applications/test/parallel-comm0/Test-parallel-comm0.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2022 OpenCFD Ltd.
+    Copyright (C) 2022-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -51,7 +51,7 @@ void printInfo(const label comm)
         << " sub:" << UPstream::subProcs(comm) << nl;
 
 
-    if (UPstream::selfComm == comm)
+    if (UPstream::commSelf() == comm)
     {
         Pout<< "self all:" << UPstream::allProcs(comm)
             << " sub:" << UPstream::subProcs(comm) << nl;
@@ -86,32 +86,32 @@ int main(int argc, char *argv[])
         << "nProcs = " << UPstream::nProcs()
         << " with " << UPstream::nComms() << " predefined comm(s)" << nl;
 
-    Info<< "worldComm : ";
-    printInfo(UPstream::worldComm);
+    Info<< "comm-world : ";
+    printInfo(UPstream::commWorld());
 
-    Info<< "selfComm  : ";
-    printInfo(UPstream::selfComm);
+    Info<< "comm-self  : ";
+    printInfo(UPstream::commSelf());
 
     Info<< nl;
 
     // Reductions (using MPI intrinsics)
     {
-        label val = Pstream::myProcNo(UPstream::worldComm);
+        label val = Pstream::myProcNo(UPstream::commWorld());
 
         label worldVal = returnReduce
         (
             val,
             sumOp<label>(),
-            Pstream::msgType(),
-            UPstream::worldComm
+            UPstream::msgType(),
+            UPstream::commWorld()
         );
 
         label selfVal = returnReduce
         (
             val,
             sumOp<label>(),
-            Pstream::msgType(),
-            UPstream::selfComm
+            UPstream::msgType(),
+            UPstream::commSelf()
         );
 
         Pout<< "value " << val
@@ -123,8 +123,8 @@ int main(int argc, char *argv[])
     {
         Pair<label> val
         (
-            Pstream::myProcNo(UPstream::worldComm),
-            Pstream::myProcNo(UPstream::worldComm)
+            Pstream::myProcNo(UPstream::commWorld()),
+            Pstream::myProcNo(UPstream::commWorld())
         );
 
         Pair<label> worldVal = val;
@@ -133,8 +133,8 @@ int main(int argc, char *argv[])
         (
             worldVal,
             minFirstEqOp<label>(),
-            Pstream::msgType(),
-            UPstream::worldComm
+            UPstream::msgType(),
+            UPstream::commWorld()
         );
 
         Pair<label> selfVal = val;
@@ -143,8 +143,8 @@ int main(int argc, char *argv[])
         (
             worldVal,
             minFirstEqOp<label>(),
-            Pstream::msgType(),
-            UPstream::selfComm
+            UPstream::msgType(),
+            UPstream::commSelf()
         );
 
         Pout<< "value " << val
diff --git a/applications/test/parallel-comm1/Test-parallel-comm1.C b/applications/test/parallel-comm1/Test-parallel-comm1.C
index 635841d6fd..bc856e781c 100644
--- a/applications/test/parallel-comm1/Test-parallel-comm1.C
+++ b/applications/test/parallel-comm1/Test-parallel-comm1.C
@@ -150,11 +150,7 @@ int main(int argc, char *argv[])
     Pout<< "localValue      :" << localValue << endl;
 
 
-    label comm = Pstream::allocateCommunicator
-    (
-        UPstream::worldComm,
-        top
-    );
+    label comm = UPstream::allocateCommunicator(UPstream::worldComm, top);
 
     Pout<< "allocated comm  :" << comm << endl;
     Pout<< "comm myproc     :" << Pstream::myProcNo(comm)
@@ -173,7 +169,7 @@ int main(int argc, char *argv[])
         Pout<< "sum             :" << sum << endl;
     }
 
-    Pstream::freeCommunicator(comm);
+    UPstream::freeCommunicator(comm);
 
 
     Pout<< "End\n" << endl;
diff --git a/applications/test/parallel-comm2/Test-parallel-comm2.C b/applications/test/parallel-comm2/Test-parallel-comm2.C
index a397c9908e..ce77d5b38c 100644
--- a/applications/test/parallel-comm2/Test-parallel-comm2.C
+++ b/applications/test/parallel-comm2/Test-parallel-comm2.C
@@ -88,12 +88,12 @@ int main(int argc, char *argv[])
 
     //- Process IDs within a given communicator
     Info<< "procIDs: "
-        << flatOutput(UPstream::procID(UPstream::worldComm)) << endl;
+        << flatOutput(UPstream::procID(UPstream::commWorld())) << endl;
 
-    rankInfo(UPstream::worldComm);
+    rankInfo(UPstream::commWorld());
     Pout<< endl;
 
-    const int myProci = UPstream::myProcNo(UPstream::worldComm);
+    const int myProci = UPstream::myProcNo(UPstream::commWorld());
     int localRanki = myProci;
 
     labelList subRanks;
@@ -101,9 +101,9 @@ int main(int argc, char *argv[])
 
     #if 1
     // With first ranks
-    subRanks = identity(UPstream::nProcs(UPstream::worldComm) / 2);
+    subRanks = identity(UPstream::nProcs(UPstream::commWorld()) / 2);
 
-    newComm.reset(UPstream::worldComm, subRanks);
+    newComm.reset(UPstream::commWorld(), subRanks);
     localRanki = UPstream::myProcNo(newComm);
 
     Pout.prefix() =
@@ -120,14 +120,14 @@ int main(int argc, char *argv[])
 
     #if 1
     // With every other rank
-    subRanks = identity(UPstream::nProcs(UPstream::worldComm));
+    subRanks = identity(UPstream::nProcs(UPstream::commWorld()));
 
     for (label& val : subRanks)
     {
         if (val % 2) val = -1;
     }
 
-    newComm.reset(UPstream::worldComm, subRanks);
+    newComm.reset(UPstream::commWorld(), subRanks);
     localRanki = UPstream::myProcNo(newComm);
 
     Pout.prefix() =
@@ -165,19 +165,19 @@ int main(int argc, char *argv[])
     }
     if (Pstream::parRun() && args.found("host-comm"))
     {
-        // Host communicator, based on the current worldComm
+        // Host communicator, based on the current world communicator
         // Use hostname
         // Lowest rank per hostname is the IO rank
 
-        label numprocs = UPstream::nProcs(UPstream::globalComm);
+        label numprocs = UPstream::nProcs(UPstream::commGlobal());
 
         stringList hosts(numprocs);
-        hosts[Pstream::myProcNo(UPstream::globalComm)] = hostName();
+        hosts[Pstream::myProcNo(UPstream::commGlobal())] = hostName();
 
         labelList hostIDs_;
 
         // Compact
-        if (Pstream::master(UPstream::globalComm))
+        if (Pstream::master(UPstream::commGlobal()))
         {
             DynamicList<word> hostNames(numprocs);
             hostIDs_.resize_nocopy(numprocs);
@@ -196,10 +196,10 @@ int main(int argc, char *argv[])
             }
         }
 
-        Pstream::broadcasts(UPstream::globalComm, hostIDs_);
+        Pstream::broadcasts(UPstream::commGlobal(), hostIDs_);
 
         const label myHostId =
-            hostIDs_[Pstream::myProcNo(UPstream::globalComm)];
+            hostIDs_[Pstream::myProcNo(UPstream::commGlobal())];
 
         DynamicList<label> subRanks;
         forAll(hostIDs_, proci)
@@ -210,11 +210,11 @@ int main(int argc, char *argv[])
             }
         }
 
-        // Allocate new communicator with globalComm as its parent
+        // Allocate new communicator with global communicator as its parent
         const label hostComm =
             UPstream::allocateCommunicator
             (
-                UPstream::globalComm,  // parent
+                UPstream::commGlobal(),
                 subRanks,
                 true
             );
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H
index e047d399bb..0bcf41e9ca 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H
@@ -58,7 +58,7 @@ void reduce
     const label comm
 )
 {
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         Pout<< "** reducing:" << value << " with comm:" << comm << endl;
         error::printStack(Pout);
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H
index 14ec039aa1..81b04bc120 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H
@@ -284,24 +284,52 @@ public:
 
     // Standard Communicators
 
-        //- Default world communicator (all processors).
+        //- Communicator for all ranks.
         //- May differ from globalComm if local worlds are in use
         static label worldComm;
 
         //- Debugging: warn for use of any communicator differing from warnComm
         static label warnComm;
 
-        //- Communicator for all processors, irrespective of any local worlds
+        //- Communicator for all ranks, irrespective of any local worlds
         static constexpr label globalComm = 0;
 
         //- A communicator within the current rank only
         static constexpr label selfComm = 1;
 
+        //- Communicator for all ranks, irrespective of any local worlds
+        static constexpr label commGlobal() noexcept { return 0; }
+
+        //- Communicator within the current rank only
+        static constexpr label commSelf() noexcept { return 1; }
+
+        //- Communicator for all ranks (respecting any local worlds)
+        static label commWorld() noexcept { return worldComm; }
+
+        //- Alter value of world communicator
+        //  \returns the previous value
+        static label commWorld(const label communicator) noexcept
+        {
+            label old(worldComm);
+            worldComm = communicator;
+            return old;
+        }
+
+        //- Alter communicator debugging setting.
+        //- Warns for use of any communicator differing from specified.
+        //  \returns the previous warn communicator
+        static label commWarn(const label communicator) noexcept
+        {
+            label old(warnComm);
+            warnComm = communicator;
+            return old;
+        }
+
         //- Number of currently defined communicators
         static label nComms() noexcept { return parentComm_.size(); }
 
         //- True if communicator appears to be user-allocated
-        static bool isUserComm(label communicator) noexcept
+        static bool isUserComm(const label communicator) noexcept
         {
             return (communicator > worldComm && communicator > selfComm);
         }
diff --git a/src/OpenFOAM/db/error/messageStream.C b/src/OpenFOAM/db/error/messageStream.C
index 55d3db1b22..0953f53d75 100644
--- a/src/OpenFOAM/db/error/messageStream.C
+++ b/src/OpenFOAM/db/error/messageStream.C
@@ -143,7 +143,7 @@ Foam::OSstream& Foam::messageStream::stream(OSstream* alternative)
 
 Foam::OSstream& Foam::messageStream::masterStream(const label communicator)
 {
-    if (UPstream::warnComm != -1 && communicator != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && communicator != UPstream::warnComm)
     {
         Pout<< "** messageStream with comm:" << communicator << endl;
         error::printStack(Pout);
diff --git a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
index f48ba801e3..b65115d7c7 100644
--- a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
+++ b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2022 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -2721,8 +2721,7 @@ void Foam::globalMeshData::updateMesh()
         identity(UPstream::nProcs(UPstream::worldComm)),
         true
     );
-    const label oldWarnComm = UPstream::warnComm;
-    UPstream::warnComm = comm;
+    const label oldWarnComm = UPstream::commWarn(comm);
 
 
     // Total number of faces.
@@ -2760,8 +2759,9 @@ void Foam::globalMeshData::updateMesh()
         comm
     );
 
+    // Restore communicator settings
     UPstream::freeCommunicator(comm);
-    UPstream::warnComm = oldWarnComm;
+    UPstream::commWarn(oldWarnComm);
 
     if (debug)
     {
diff --git a/src/Pstream/mpi/UIPstreamRead.C b/src/Pstream/mpi/UIPstreamRead.C
index e2ecbc0da8..e7bb303da0 100644
--- a/src/Pstream/mpi/UIPstreamRead.C
+++ b/src/Pstream/mpi/UIPstreamRead.C
@@ -114,7 +114,7 @@ Foam::label Foam::UIPstream::read
             << " commsType:" << UPstream::commsTypeNames[commsType]
             << Foam::endl;
     }
-    if (UPstream::warnComm != -1 && communicator != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && communicator != UPstream::warnComm)
     {
         Pout<< "UIPstream::read : starting read from:" << fromProcNo
             << " tag:" << tag << " comm:" << communicator
diff --git a/src/Pstream/mpi/UOPstreamWrite.C b/src/Pstream/mpi/UOPstreamWrite.C
index 5982e99cae..a971799ac9 100644
--- a/src/Pstream/mpi/UOPstreamWrite.C
+++ b/src/Pstream/mpi/UOPstreamWrite.C
@@ -68,7 +68,7 @@ bool Foam::UOPstream::write
             << " commType:" << UPstream::commsTypeNames[commsType]
             << Foam::endl;
     }
-    if (UPstream::warnComm != -1 && communicator != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && communicator != UPstream::warnComm)
     {
         Pout<< "UOPstream::write : starting write to:" << toProcNo
             << " tag:" << tag
diff --git a/src/Pstream/mpi/UPstreamBroadcast.C b/src/Pstream/mpi/UPstreamBroadcast.C
index af061bd76c..f5044970c7 100644
--- a/src/Pstream/mpi/UPstreamBroadcast.C
+++ b/src/Pstream/mpi/UPstreamBroadcast.C
@@ -54,7 +54,7 @@ bool Foam::UPstream::broadcast
             << " size:" << label(bufSize)
             << Foam::endl;
     }
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         Pout<< "UPstream::broadcast : root:" << rootProcNo
             << " comm:" << comm
diff --git a/src/Pstream/mpi/UPstreamWrappingTemplates.C b/src/Pstream/mpi/UPstreamWrappingTemplates.C
index 92fe2b6852..b93f9d447b 100644
--- a/src/Pstream/mpi/UPstreamWrappingTemplates.C
+++ b/src/Pstream/mpi/UPstreamWrappingTemplates.C
@@ -78,7 +78,7 @@ void Foam::PstreamDetail::reduce0
         return;
     }
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         Pout<< "** reducing:";
         if (count == 1)
@@ -135,7 +135,7 @@ void Foam::PstreamDetail::allReduce
 
     const bool immediate = (req || requestID);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         if (immediate)
         {
@@ -246,7 +246,7 @@ void Foam::PstreamDetail::allToAll
 
     const label numProc = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         if (immediate)
         {
@@ -383,7 +383,7 @@ void Foam::PstreamDetail::allToAllv
 
     const label np = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         if (immediate)
         {
@@ -531,7 +531,7 @@ void Foam::PstreamDetail::allToAllConsensus
     const label myProci = UPstream::myProcNo(comm);
     const label numProc = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         Pout<< "** non-blocking consensus Alltoall (list):";
         Pout<< " numProc:" << numProc
@@ -717,7 +717,7 @@ void Foam::PstreamDetail::allToAllConsensus
     const label myProci = UPstream::myProcNo(comm);
     const label numProc = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         Pout<< "** non-blocking consensus Alltoall (map):";
         Pout<< " numProc:" << numProc
@@ -911,7 +911,7 @@ void Foam::PstreamDetail::gather
 
     const label np = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         if (immediate)
         {
@@ -1037,7 +1037,7 @@ void Foam::PstreamDetail::scatter
 
     const label np = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         if (immediate)
         {
@@ -1165,7 +1165,7 @@ void Foam::PstreamDetail::gatherv
 
     const label np = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         if (immediate)
         {
@@ -1317,7 +1317,7 @@ void Foam::PstreamDetail::scatterv
 
     const label np = UPstream::nProcs(comm);
 
-    if (UPstream::warnComm != -1 && comm != UPstream::warnComm)
+    if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
         if (immediate)
         {
diff --git a/src/functionObjects/utilities/syncObjects/syncObjects.C b/src/functionObjects/utilities/syncObjects/syncObjects.C
index 06776eae3b..cd5b2c2a64 100644
--- a/src/functionObjects/utilities/syncObjects/syncObjects.C
+++ b/src/functionObjects/utilities/syncObjects/syncObjects.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2020-2022 OpenCFD Ltd.
+    Copyright (C) 2020-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -80,8 +80,7 @@ void Foam::functionObjects::syncObjects::sync()
         return;
     }
 
-    const label oldWarnComm = UPstream::warnComm;
-    UPstream::warnComm = 0;
+    const label oldWarnComm = UPstream::commWarn(UPstream::commGlobal());
 
 
     // Send my data to all other processors
@@ -90,7 +89,7 @@ void Foam::functionObjects::syncObjects::sync()
     // Note provision of explicit all-world communicator
     PstreamBuffers pBufs
     (
-        UPstream::globalComm,
+        UPstream::commGlobal(),
         UPstream::commsTypes::nonBlocking
     );
 
@@ -164,7 +163,8 @@ void Foam::functionObjects::syncObjects::sync()
     //    Pout<< type() << " : after synchronisation:" << allDict << endl;
     //}
 
-    UPstream::warnComm = oldWarnComm;
+    // Restore communicator settings
+    UPstream::commWarn(oldWarnComm);
 }
 
 
diff --git a/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBase.C b/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBase.C
index 7c1ed9f155..92421c80f5 100644
--- a/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBase.C
+++ b/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBase.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2022 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -133,7 +133,7 @@ Foam::label Foam::mappedPatchBase::getWorldCommunicator() const
 {
     if (sameWorld())
     {
-        return UPstream::worldComm;
+        return UPstream::commWorld();
     }
 
     const Time& runTime = patch_.boundaryMesh().mesh().time();
@@ -187,8 +187,7 @@ void Foam::mappedPatchBase::collectSamples
     const label myRank = Pstream::myProcNo(myComm);
     const label nProcs = Pstream::nProcs(myComm);
 
-    const label oldWarnComm(Pstream::warnComm);
-    Pstream::warnComm = myComm;
+    const label oldWarnComm = UPstream::commWarn(myComm);
 
     if (debug & 2)
     {
@@ -265,7 +264,8 @@ void Foam::mappedPatchBase::collectSamples
         }
     }
 
-    Pstream::warnComm = oldWarnComm;
+    // Restore communicator settings
+    UPstream::commWarn(oldWarnComm);
 }
 
 
@@ -591,8 +591,7 @@ void Foam::mappedPatchBase::findSamples
     const label myRank = Pstream::myProcNo(myComm);
     const label nProcs = Pstream::nProcs(myComm);
 
-    const label oldWarnComm(Pstream::warnComm);
-    Pstream::warnComm = myComm;
+    const label oldWarnComm = UPstream::commWarn(myComm);
 
     wordList samplePatches(nProcs);
     {
@@ -711,7 +710,8 @@ void Foam::mappedPatchBase::findSamples
         }
     }
 
-    Pstream::warnComm = oldWarnComm;
+    // Return communicator settings
+    UPstream::commWarn(oldWarnComm);
 }
 
 
@@ -1105,9 +1105,6 @@ void Foam::mappedPatchBase::calcAMI() const
     // Pre-calculate surface (if any)
     const auto& surf = surfPtr();
 
-    const label oldWorldComm(Pstream::worldComm);
-    const label oldWarnComm(Pstream::warnComm);
-
     // Check if running locally
     if (sampleWorld_.empty() || sameWorld())
     {
@@ -1143,13 +1140,14 @@ void Foam::mappedPatchBase::calcAMI() const
         // weights.
 
         // Change to use inter-world communicator
-        Pstream::worldComm = myComm;
-        Pstream::warnComm = Pstream::worldComm;
+        const label oldWarnComm = UPstream::commWarn(myComm);
+        const label oldWorldComm = UPstream::commWorld(myComm);
 
         AMIPtr_->calculate(patch_, nbrPatch0, surf);
 
-        Pstream::warnComm = oldWarnComm;
-        Pstream::worldComm = oldWorldComm;
+        // Restore communicator settings
+        UPstream::commWarn(oldWarnComm);
+        UPstream::commWorld(oldWorldComm);
     }
     else
     {
@@ -1162,8 +1160,8 @@ void Foam::mappedPatchBase::calcAMI() const
         );
 
         // Change to use inter-world communicator
-        Pstream::worldComm = myComm;
-        Pstream::warnComm = Pstream::worldComm;
+        const label oldWarnComm = UPstream::commWarn(myComm);
+        const label oldWorldComm = UPstream::commWorld(myComm);
 
         if (masterWorld())
         {
@@ -1182,8 +1180,9 @@ void Foam::mappedPatchBase::calcAMI() const
         // Now the AMI addressing/weights will be from src side (on masterWorld
         // processors) to tgt side (on other processors)
 
-        Pstream::warnComm = oldWarnComm;
-        Pstream::worldComm = oldWorldComm;
+        // Restore communicator settings
+        UPstream::commWarn(oldWarnComm);
+        UPstream::commWorld(oldWorldComm);
     }
 }
 
diff --git a/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBaseTemplates.C b/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBaseTemplates.C
index 7e93773202..e4ee68ab43 100644
--- a/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBaseTemplates.C
+++ b/src/meshTools/mappedPatches/mappedPolyPatch/mappedPatchBaseTemplates.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2018-2022 OpenCFD Ltd.
+    Copyright (C) 2018-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -30,17 +30,14 @@ template<class Type>
 void Foam::mappedPatchBase::distribute(List<Type>& lst) const
 {
     const label myComm = getCommunicator();  // Get or create
-    const label oldWarnComm(Pstream::warnComm);
 
     switch (mode_)
     {
         case NEARESTPATCHFACEAMI:
         {
-            const label oldWorldComm(Pstream::worldComm);
             const auto& interp = AMI();
-
-            Pstream::warnComm = myComm;
-            Pstream::worldComm = myComm;
+            const label oldWarnComm = UPstream::commWarn(myComm);
+            const label oldWorldComm = UPstream::commWorld(myComm);
 
             if (sameWorld())
             {
@@ -87,17 +84,20 @@ void Foam::mappedPatchBase::distribute(List<Type>& lst) const
                     lst = tmasterFld;
                 }
             }
-            Pstream::worldComm = oldWorldComm;
-            Pstream::warnComm = oldWarnComm;
+
+            // Restore communicator settings
+            UPstream::commWarn(oldWarnComm);
+            UPstream::commWorld(oldWorldComm);
             break;
         }
         default:
         {
             const auto& m = map();
+            const label oldWarnComm = UPstream::commWarn(m.comm());
 
-            Pstream::warnComm = m.comm();
             m.distribute(lst);
-            Pstream::warnComm = oldWarnComm;
+
+            UPstream::commWarn(oldWarnComm);
         }
     }
 }
@@ -111,19 +111,19 @@ void Foam::mappedPatchBase::distribute
 ) const
 {
     const label myComm = getCommunicator();  // Get or create
-    const label oldWarnComm(Pstream::warnComm);
 
     switch (mode_)
     {
         case NEARESTPATCHFACEAMI:
         {
-            const label oldWorldComm(Pstream::worldComm);
             const auto& interp = AMI();
-            Pstream::warnComm = myComm;
-            Pstream::worldComm = myComm;
+            const label oldWarnComm = UPstream::commWarn(myComm);
+            const label oldWorldComm = UPstream::commWorld(myComm);
+
             lst = interp.interpolateToSource(Field<Type>(std::move(lst)), cop);
-            Pstream::worldComm = oldWorldComm;
-            Pstream::warnComm = oldWarnComm;
+
+            UPstream::commWarn(oldWarnComm);
+            UPstream::commWorld(oldWorldComm);
             break;
         }
         default:
@@ -132,7 +132,7 @@ void Foam::mappedPatchBase::distribute
             (void)patch_.boundaryMesh().mesh().tetBasePtIs();
             const auto& m = map();
 
-            Pstream::warnComm = myComm;
+            const label oldWarnComm = UPstream::commWarn(myComm);
             mapDistributeBase::distribute
             (
                 Pstream::defaultCommsType,
@@ -149,7 +149,7 @@ void Foam::mappedPatchBase::distribute
                 UPstream::msgType(),
                 myComm
             );
-            Pstream::warnComm = oldWarnComm;
+            UPstream::commWarn(oldWarnComm);
         }
     }
 }
@@ -159,19 +159,19 @@ template<class Type>
 void Foam::mappedPatchBase::reverseDistribute(List<Type>& lst) const
 {
     const label myComm = getCommunicator();  // Get or create
-    const label oldWarnComm(Pstream::warnComm);
 
     switch (mode_)
     {
         case NEARESTPATCHFACEAMI:
         {
-            const label oldWorldComm(Pstream::worldComm);
             const auto& interp = AMI();
-            Pstream::warnComm = myComm;
-            Pstream::worldComm = myComm;
+            const label oldWarnComm = UPstream::commWarn(myComm);
+            const label oldWorldComm = UPstream::commWorld(myComm);
+
             lst = interp.interpolateToTarget(Field<Type>(std::move(lst)));
-            Pstream::worldComm = oldWorldComm;
-            Pstream::warnComm = oldWarnComm;
+
+            UPstream::commWarn(oldWarnComm);
+            UPstream::commWorld(oldWorldComm);
             break;
         }
         default:
@@ -180,9 +180,9 @@ void Foam::mappedPatchBase::reverseDistribute(List<Type>& lst) const
             (void)patch_.boundaryMesh().mesh().tetBasePtIs();
             const auto& m = map();
 
-            Pstream::warnComm = m.comm();
+            const label oldWarnComm = UPstream::commWarn(m.comm());
             m.reverseDistribute(sampleSize(), lst);
-            Pstream::warnComm = oldWarnComm;
+            UPstream::commWarn(oldWarnComm);
             break;
         }
     }
@@ -197,19 +197,19 @@ void Foam::mappedPatchBase::reverseDistribute
 ) const
 {
     const label myComm = getCommunicator();  // Get or create
-    const label oldWarnComm(Pstream::warnComm);
 
     switch (mode_)
     {
         case NEARESTPATCHFACEAMI:
         {
-            const label oldWorldComm(Pstream::worldComm);
             const auto& interp = AMI();
-            Pstream::warnComm = myComm;
-            Pstream::worldComm = myComm;
+            const label oldWarnComm = UPstream::commWarn(myComm);
+            const label oldWorldComm = UPstream::commWorld(myComm);
+
             lst = interp.interpolateToTarget(Field<Type>(std::move(lst)), cop);
-            Pstream::worldComm = oldWorldComm;
-            Pstream::warnComm = oldWarnComm;
+
+            UPstream::commWarn(oldWarnComm);
+            UPstream::commWorld(oldWorldComm);
             break;
         }
         default:
@@ -217,7 +217,9 @@ void Foam::mappedPatchBase::reverseDistribute
             (void)patch_.boundaryMesh().mesh().tetBasePtIs();
             const auto& m = map();
             const label cSize = sampleSize();
-            Pstream::warnComm = myComm;
+
+            const label oldWarnComm = UPstream::commWarn(myComm);
+
             mapDistributeBase::distribute
             (
                 Pstream::defaultCommsType,
@@ -234,7 +236,8 @@ void Foam::mappedPatchBase::reverseDistribute
                 UPstream::msgType(),
                 myComm
             );
-            Pstream::warnComm = oldWarnComm;
+
+            UPstream::commWarn(oldWarnComm);
             break;
         }
     }
diff --git a/src/meshTools/multiWorld/multiWorldConnectionsObject.C b/src/meshTools/multiWorld/multiWorldConnectionsObject.C
index 43e736228b..8b752d289a 100644
--- a/src/meshTools/multiWorld/multiWorldConnectionsObject.C
+++ b/src/meshTools/multiWorld/multiWorldConnectionsObject.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2021-2022 OpenCFD Ltd.
+    Copyright (C) 2021-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -162,7 +162,8 @@ Foam::label Foam::multiWorldConnections::createCommunicator(const edge& worlds)
     }
 
     // Allocate new communicator with global world
-    comm = UPstream::allocateCommunicator(UPstream::globalComm, subRanks, true);
+    comm =
+        UPstream::allocateCommunicator(UPstream::commGlobal(), subRanks, true);
 
     if (debug & 2)
     {
@@ -234,10 +235,8 @@ void Foam::multiWorldConnections::createComms()
 
 
     // Use MPI_COMM_WORLD
-    const label oldWorldComm(UPstream::worldComm);
-    const label oldWarnComm(UPstream::warnComm);
-    UPstream::worldComm = UPstream::globalComm;
-    UPstream::warnComm = UPstream::worldComm;
+    const label oldWarnComm = UPstream::commWarn(UPstream::commGlobal());
+    const label oldWorldComm = UPstream::commWorld(UPstream::commGlobal());
 
     if (Pstream::parRun())
     {
@@ -258,8 +257,9 @@ void Foam::multiWorldConnections::createComms()
 
     if (brokenConnections)
     {
-        Pstream::warnComm = oldWarnComm;
-        Pstream::worldComm = oldWorldComm;
+        // Restore communicator settings
+        UPstream::commWarn(oldWarnComm);
+        UPstream::commWorld(oldWorldComm);
 
         FatalErrorInFunction
             << "Has " << brokenConnections
@@ -286,8 +286,9 @@ void Foam::multiWorldConnections::createComms()
             }
         }
 
-        Pstream::warnComm = oldWarnComm;
-        Pstream::worldComm = oldWorldComm;
+        // Restore communicator settings
+        UPstream::commWarn(oldWarnComm);
+        UPstream::commWorld(oldWorldComm);
     }
 
     if (debug)