diff --git a/.gitlab/issue_templates/bug.md b/.gitlab/issue_templates/bug.md
index 11dfe59470..9865f5a4fb 100644
--- a/.gitlab/issue_templates/bug.md
+++ b/.gitlab/issue_templates/bug.md
@@ -49,7 +49,7 @@
 
 <!--
   Providing details of your set-up can help us identify any issues, e.g.
-  OpenFOAM version : v1806|v1812|v1906 etc
+  OpenFOAM version : v1806|v1812|v1906|v1912|v2006|v2012|v2106 etc
   Operating system : ubuntu|openSUSE|centos etc
   Hardware info    : any info that may help?
   Compiler         : gcc|intel|clang etc
diff --git a/doc/Build.md b/doc/Build.md
index 7853943b80..b5b61d2757 100644
--- a/doc/Build.md
+++ b/doc/Build.md
@@ -1,3 +1,10 @@
+## Getting the code
+
+Links to all code packs are available on https://dl.openfoam.com. For OpenFOAM-v2106:
+
+- Source: https://dl.openfoam.com/source/v2106/OpenFOAM-v2106.tgz
+- ThirdParty: https://dl.openfoam.com/source/v2106/ThirdParty-v2106.tgz
+
 ## OpenFOAM&reg; Quick Build Guide
 
 Prior to building, ensure that the [system requirements][link openfoam-require]
diff --git a/src/OpenFOAM/db/runTimeSelection/construction/runTimeSelectionTables.H b/src/OpenFOAM/db/runTimeSelection/construction/runTimeSelectionTables.H
index 336927c38f..a6a2a528df 100644
--- a/src/OpenFOAM/db/runTimeSelection/construction/runTimeSelectionTables.H
+++ b/src/OpenFOAM/db/runTimeSelection/construction/runTimeSelectionTables.H
@@ -52,8 +52,12 @@ Description
     typedef autoPtr<baseType> (*argNames##ConstructorPtr)argList;              \
                                                                                \
     /* Construct from argList function table type */                           \
-    typedef HashTable<argNames##ConstructorPtr, word>                          \
-        argNames##ConstructorTable;                                            \
+    typedef HashTable                                                          \
+    <                                                                          \
+        argNames##ConstructorPtr,                                              \
+        ::Foam::word,                                                          \
+        ::Foam::string::hasher                                                 \
+    > argNames##ConstructorTable;                                              \
                                                                                \
     /* Construct from argList function pointer table pointer */                \
     static argNames##ConstructorTable* argNames##ConstructorTablePtr_;         \
@@ -77,7 +81,7 @@ Description
                                                                                \
         explicit add##argNames##ConstructorToTable                             \
         (                                                                      \
-            const word& lookup = baseType##Type::typeName                      \
+            const ::Foam::word& lookup = baseType##Type::typeName              \
         )                                                                      \
         {                                                                      \
             construct##argNames##ConstructorTables();                          \
@@ -109,7 +113,7 @@ Description
     {                                                                          \
     public:                                                                    \
                                                                                \
-        const word name;  /* Lookup name for later removal */                  \
+        const ::Foam::word name;  /* Lookup name for later removal */          \
                                                                                \
         static autoPtr<baseType> New argList                                   \
         {                                                                      \
@@ -118,7 +122,7 @@ Description
                                                                                \
         explicit addRemovable##argNames##ConstructorToTable                    \
         (                                                                      \
-            const word& lookup = baseType##Type::typeName                      \
+            const ::Foam::word& lookup = baseType##Type::typeName              \
         )                                                                      \
         :                                                                      \
             name(lookup)                                                       \
@@ -152,8 +156,12 @@ Description
     typedef autoPtr<baseType> (*argNames##ConstructorPtr)argList;              \
                                                                                \
     /* Construct from argList function table type */                           \
-    typedef HashTable<argNames##ConstructorPtr, word>                          \
-        argNames##ConstructorTable;                                            \
+    typedef HashTable                                                          \
+    <                                                                          \
+        argNames##ConstructorPtr,                                              \
+        ::Foam::word,                                                          \
+        ::Foam::string::hasher                                                 \
+    > argNames##ConstructorTable;                                              \
                                                                                \
     /* Construct from argList function pointer table pointer */                \
     static argNames##ConstructorTable* argNames##ConstructorTablePtr_;         \
@@ -177,7 +185,7 @@ Description
                                                                                \
         explicit add##argNames##ConstructorToTable                             \
         (                                                                      \
-            const word& lookup = baseType##Type::typeName                      \
+            const ::Foam::word& lookup = baseType##Type::typeName              \
         )                                                                      \
         {                                                                      \
             construct##argNames##ConstructorTables();                          \
@@ -215,7 +223,7 @@ Description
     {                                                                          \
     public:                                                                    \
                                                                                \
-        const word name;  /* Lookup name for later removal */                  \
+        const ::Foam::word name;  /* Lookup name for later removal */          \
                                                                                \
         static autoPtr<baseType> New##baseType argList                         \
         {                                                                      \
@@ -224,7 +232,7 @@ Description
                                                                                \
         explicit addRemovable##argNames##ConstructorToTable                    \
         (                                                                      \
-            const word& lookup = baseType##Type::typeName                      \
+            const ::Foam::word& lookup = baseType##Type::typeName              \
         )                                                                      \
         :                                                                      \
             name(lookup)                                                       \
diff --git a/src/OpenFOAM/db/runTimeSelection/memberFunctions/memberFunctionSelectionTables.H b/src/OpenFOAM/db/runTimeSelection/memberFunctions/memberFunctionSelectionTables.H
index a92954fbd6..df70160dad 100644
--- a/src/OpenFOAM/db/runTimeSelection/memberFunctions/memberFunctionSelectionTables.H
+++ b/src/OpenFOAM/db/runTimeSelection/memberFunctions/memberFunctionSelectionTables.H
@@ -46,8 +46,12 @@ Description
     typedef returnType (*memberFunction##argNames##MemberFunctionPtr)argList;  \
                                                                                \
     /* Construct from argList function table type */                           \
-    typedef HashTable<memberFunction##argNames##MemberFunctionPtr, word>       \
-        memberFunction##argNames##MemberFunctionTable;                         \
+    typedef HashTable                                                          \
+    <                                                                          \
+        memberFunction##argNames##MemberFunctionPtr,                           \
+        ::Foam::word,                                                          \
+        ::Foam::string::hasher                                                 \
+    > memberFunction##argNames##MemberFunctionTable;                           \
                                                                                \
     /* Construct from argList function pointer table pointer */                \
     static memberFunction##argNames##MemberFunctionTable*                      \
@@ -61,7 +65,7 @@ Description
                                                                                \
         explicit add##memberFunction##argNames##MemberFunctionToTable          \
         (                                                                      \
-            const word& lookup = baseType##Type::typeName                      \
+            const ::Foam::word& lookup = baseType##Type::typeName              \
         )                                                                      \
         {                                                                      \
             construct##memberFunction##argNames##MemberFunctionTables();       \
diff --git a/src/OpenFOAM/primitives/strings/word/wordIO.C b/src/OpenFOAM/primitives/strings/word/wordIO.C
index 03e46193ca..060b871d3b 100644
--- a/src/OpenFOAM/primitives/strings/word/wordIO.C
+++ b/src/OpenFOAM/primitives/strings/word/wordIO.C
@@ -48,15 +48,16 @@ Foam::Istream& Foam::operator>>(Istream& is, word& val)
     {
         val = tok.wordToken();
     }
-    else if (tok.isQuotedString())
+    else if (tok.isQuotedString() || tok.isVariable())
     {
-        // Try a bit harder and convert string to word
-        val = tok.stringToken();
-        const auto oldLen = val.length();
-        string::stripInvalid<word>(val);
+        // Try a bit harder, convert some string types to word
+        // - accept "quoted" or $tag, but not verbatim/expression
+
+        const auto& str = tok.stringToken();
+        val = word::validate(str);
 
         // Flag empty strings and bad chars as an error
-        if (val.empty() || val.length() != oldLen)
+        if (val.empty() || val.length() != str.length())
         {
             FatalIOErrorInFunction(is)
                 << "Empty word or non-word characters "
diff --git a/src/functionObjects/field/Curle/Curle.C b/src/functionObjects/field/Curle/Curle.C
index 39f38def4e..1a8133a83d 100644
--- a/src/functionObjects/field/Curle/Curle.C
+++ b/src/functionObjects/field/Curle/Curle.C
@@ -213,11 +213,11 @@ bool Foam::functionObjects::Curle::execute()
 
         forAll(observerPositions_, pointi)
         {
-            const vectorField r(Cfp - observerPositions_[pointi]);
+            const vectorField r(observerPositions_[pointi] - Cfp);
             const scalarField invMagR(1/(mag(r) + ROOTVSMALL));
 
             pDash[pointi] +=
-                sum((pp*sqr(invMagR) + invMagR/c0_*dpdtp)*(Sfp & r));
+                sum((pp*sqr(invMagR) + invMagR/c0_*dpdtp)*(Sfp & (r*invMagR)));
         }
     }
 
diff --git a/src/lagrangian/intermediate/submodels/CloudFunctionObjects/ParticleCollector/ParticleCollector.C b/src/lagrangian/intermediate/submodels/CloudFunctionObjects/ParticleCollector/ParticleCollector.C
index c6a9371728..6c4c3aae34 100644
--- a/src/lagrangian/intermediate/submodels/CloudFunctionObjects/ParticleCollector/ParticleCollector.C
+++ b/src/lagrangian/intermediate/submodels/CloudFunctionObjects/ParticleCollector/ParticleCollector.C
@@ -419,8 +419,6 @@ void Foam::ParticleCollector<CloudType>::write()
         massTotal_[facei] += mass_[facei];
     }
 
-    const label proci = Pstream::myProcNo();
-
     Info<< type() << " output:" << nl;
 
     Field<scalar> faceMassTotal(mass_.size(), Zero);
@@ -434,15 +432,11 @@ void Foam::ParticleCollector<CloudType>::write()
     scalar sumAverageMFR = 0.0;
     forAll(faces_, facei)
     {
-        scalarList allProcMass(Pstream::nProcs());
-        allProcMass[proci] = massTotal_[facei];
-        Pstream::gatherList(allProcMass);
-        faceMassTotal[facei] += sum(allProcMass);
+        faceMassTotal[facei] +=
+            returnReduce(massTotal_[facei], sumOp<scalar>());
 
-        scalarList allProcMassFlowRate(Pstream::nProcs());
-        allProcMassFlowRate[proci] = massFlowRate_[facei];
-        Pstream::gatherList(allProcMassFlowRate);
-        faceMassFlowRate[facei] += sum(allProcMassFlowRate);
+        faceMassFlowRate[facei] +=
+            returnReduce(massFlowRate_[facei], sumOp<scalar>());
 
         sumTotalMass += faceMassTotal[facei];
         sumAverageMFR += faceMassFlowRate[facei];
diff --git a/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.C b/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.C
index 2300c14ea8..94a63e2a51 100644
--- a/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.C
+++ b/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015 OpenFOAM Foundation
-    Copyright (C) 2015-2020 OpenCFD Ltd.
+    Copyright (C) 2015-2021 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -108,6 +108,57 @@ Foam::surfaceWriters::boundaryDataWriter::boundaryDataWriter
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+void Foam::surfaceWriters::boundaryDataWriter::serialWriteGeometry
+(
+    const regIOobject& iopts,
+    const meshedSurf& surf
+)
+{
+    const pointField& points = surf.points();
+    const faceList& faces = surf.faces();
+
+    if (verbose_)
+    {
+        if (this->isPointData())
+        {
+            Info<< "Writing points: " << iopts.objectPath() << endl;
+        }
+        else
+        {
+            Info<< "Writing face centres: " << iopts.objectPath() << endl;
+        }
+    }
+
+    // Like regIOobject::writeObject without instance() adaptation
+    // since this would write to e.g. 0/ instead of postProcessing/
+
+    OFstream osGeom(iopts.objectPath(), streamOpt_);
+
+    if (header_)
+    {
+        iopts.writeHeader(osGeom);
+    }
+
+    if (this->isPointData())
+    {
+        // Just like writeData, but without copying beforehand
+        osGeom << points;
+    }
+    else
+    {
+        primitivePatch pp(SubList<face>(faces), points);
+
+        // Just like writeData, but without copying beforehand
+        osGeom << pp.faceCentres();
+    }
+
+    if (header_)
+    {
+        iopts.writeEndDivider(osGeom);
+    }
+}
+
+
 Foam::fileName Foam::surfaceWriters::boundaryDataWriter::write()
 {
     checkOpen();
@@ -129,6 +180,7 @@ Foam::fileName Foam::surfaceWriters::boundaryDataWriter::write()
             mkDir(surfaceDir);
         }
 
+        // Write sample locations
         pointIOField iopts
         (
             IOobject
@@ -140,30 +192,9 @@ Foam::fileName Foam::surfaceWriters::boundaryDataWriter::write()
                 false
             )
         );
+        iopts.note() = (this->isPointData() ? "point data" : "face data");
 
-        if (verbose_)
-        {
-            Info<< "Writing points: " << iopts.objectPath() << endl;
-        }
-
-
-        // Like regIOobject::writeObject without instance() adaptation
-        // since this would write to e.g. 0/ instead of postProcessing/
-
-        OFstream osGeom(iopts.objectPath(), streamOpt_);
-
-        if (header_)
-        {
-            iopts.writeHeader(osGeom);
-        }
-
-        // Just like writeData, but without copying beforehand
-        osGeom << surf.points();
-
-        if (header_)
-        {
-            iopts.writeEndDivider(osGeom);
-        }
+        serialWriteGeometry(iopts, surf);
     }
 
     wroteGeom_ = true;
@@ -212,67 +243,29 @@ Foam::fileName Foam::surfaceWriters::boundaryDataWriter::writeTemplate
 
     if (Pstream::master() || !parallel_)
     {
-        const pointField& points = surf.points();
-        const faceList& faces = surf.faces();
-
         if (!isDir(outputFile.path()))
         {
             mkDir(outputFile.path());
         }
 
-        pointIOField iopts
-        (
-            IOobject
+        // Write sample locations
+        {
+            pointIOField iopts
             (
-                surfaceDir/"points",
-                *dummyTimePtr,
-                IOobject::NO_READ,
-                IOobject::NO_WRITE,
-                false
-            )
-        );
+                IOobject
+                (
+                    surfaceDir/"points",
+                    *dummyTimePtr,
+                    IOobject::NO_READ,
+                    IOobject::NO_WRITE,
+                    false
+                )
+            );
+            iopts.note() = (this->isPointData() ? "point data" : "face data");
 
-        if (verbose_)
-        {
-            if (this->isPointData())
-            {
-                Info<< "Writing points: " << iopts.objectPath() << endl;
-            }
-            else
-            {
-                Info<< "Writing face centres: " << iopts.objectPath() << endl;
-            }
+            serialWriteGeometry(iopts, surf);
         }
 
-        // Like regIOobject::writeObject without instance() adaptation
-        // since this would write to e.g. 0/ instead of postProcessing/
-
-        OFstream osGeom(iopts.objectPath(), streamOpt_);
-
-        if (header_)
-        {
-            iopts.writeHeader(osGeom);
-        }
-
-        if (this->isPointData())
-        {
-            // Just like writeData, but without copying beforehand
-            osGeom << points;
-        }
-        else
-        {
-            primitivePatch pp(SubList<face>(faces), points);
-
-            // Just like writeData, but without copying beforehand
-            osGeom << pp.faceCentres();
-        }
-
-        if (header_)
-        {
-            iopts.writeEndDivider(osGeom);
-        }
-
-
         // Write field
         {
             IOField<Type> iofld
@@ -286,6 +279,7 @@ Foam::fileName Foam::surfaceWriters::boundaryDataWriter::writeTemplate
                     false
                 )
             );
+            iofld.note() = (this->isPointData() ? "point data" : "face data");
 
             OFstream osField(iofld.objectPath(), streamOpt_);
 
diff --git a/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.H b/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.H
index f8628882fe..ec7df24459 100644
--- a/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.H
+++ b/src/surfMesh/writers/boundaryData/boundaryDataSurfaceWriter.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2015-2020 OpenCFD Ltd.
+    Copyright (C) 2015-2021 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -134,6 +134,10 @@ SourceFiles
 
 namespace Foam
 {
+
+// Forward Declarations
+class regIOobject;
+
 namespace surfaceWriters
 {
 
@@ -159,6 +163,9 @@ class boundaryDataWriter
 
     // Private Member Functions
 
+        //- Write serial surface geometry to "points" file.
+        void serialWriteGeometry(const regIOobject&, const meshedSurf& surf);
+
         //- Templated write field operation
         template<class Type>
         fileName writeTemplate