diff --git a/src/Mod/Import/App/AppImportPy.cpp b/src/Mod/Import/App/AppImportPy.cpp
index 9a47dfcd63..069a9aee98 100644
--- a/src/Mod/Import/App/AppImportPy.cpp
+++ b/src/Mod/Import/App/AppImportPy.cpp
@@ -356,12 +356,7 @@ private:
                 // writer.SetColorMode(Standard_False);
                 writer.Transfer(hDoc, STEPControl_AsIs);
 
-                // edit STEP header
-#if OCC_VERSION_HEX >= 0x060500
                 APIHeaderSection_MakeHeader makeHeader(writer.ChangeWriter().Model());
-#else
-                APIHeaderSection_MakeHeader makeHeader(writer.Writer().Model());
-#endif
                 Base::Reference<ParameterGrp> hGrp = App::GetApplication().GetUserParameter()
                     .GetGroup("BaseApp")->GetGroup("Preferences")->GetGroup("Mod/Part")->GetGroup("STEP");
 
diff --git a/src/Mod/Import/App/ExportOCAF.cpp b/src/Mod/Import/App/ExportOCAF.cpp
index 3a76769b42..b237a4213c 100644
--- a/src/Mod/Import/App/ExportOCAF.cpp
+++ b/src/Mod/Import/App/ExportOCAF.cpp
@@ -73,11 +73,7 @@
 # include <TopoDS_Iterator.hxx>
 # include <APIHeaderSection_MakeHeader.hxx>
 # include <OSD_Exception.hxx>
-#if OCC_VERSION_HEX >= 0x060500
 # include <TDataXtd_Shape.hxx>
-# else
-# include <TDataStd_Shape.hxx>
-# endif
 #endif
 
 #include <Base/Console.h>
diff --git a/src/Mod/Import/App/ImportOCAF.cpp b/src/Mod/Import/App/ImportOCAF.cpp
index b0801c5c4a..978674db4e 100644
--- a/src/Mod/Import/App/ImportOCAF.cpp
+++ b/src/Mod/Import/App/ImportOCAF.cpp
@@ -75,11 +75,7 @@
 # include <TopoDS_Iterator.hxx>
 # include <APIHeaderSection_MakeHeader.hxx>
 # include <OSD_Exception.hxx>
-#if OCC_VERSION_HEX >= 0x060500
 # include <TDataXtd_Shape.hxx>
-# else
-# include <TDataStd_Shape.hxx>
-# endif
 #endif
 
 #include <boost/algorithm/string.hpp>
diff --git a/src/Mod/Import/App/ImportOCAFAssembly.cpp b/src/Mod/Import/App/ImportOCAFAssembly.cpp
index bd0d681019..084124a7ef 100644
--- a/src/Mod/Import/App/ImportOCAFAssembly.cpp
+++ b/src/Mod/Import/App/ImportOCAFAssembly.cpp
@@ -56,11 +56,7 @@
 # include <TopoDS_Iterator.hxx>
 # include <APIHeaderSection_MakeHeader.hxx>
 # include <OSD_Exception.hxx>
-#if OCC_VERSION_HEX >= 0x060500
 # include <TDataXtd_Shape.hxx>
-# else
-# include <TDataStd_Shape.hxx>
-# endif
 #endif
 
 #include "ImportOCAFAssembly.h"
diff --git a/src/Mod/Import/Gui/AppImportGuiPy.cpp b/src/Mod/Import/Gui/AppImportGuiPy.cpp
index 4377092bc1..8d6bc08038 100644
--- a/src/Mod/Import/Gui/AppImportGuiPy.cpp
+++ b/src/Mod/Import/Gui/AppImportGuiPy.cpp
@@ -71,11 +71,7 @@
 # include <XSControl_TransferReader.hxx>
 # include <XSControl_WorkSession.hxx>
 
-#if OCC_VERSION_HEX >= 0x060500
 # include <TDataXtd_Shape.hxx>
-# else
-# include <TDataStd_Shape.hxx>
-# endif
 #if OCC_VERSION_HEX >= 0x070500
 # include <Message_ProgressRange.hxx>
 # include <RWGltf_CafWriter.hxx>
@@ -644,11 +640,8 @@ private:
                 writer.Transfer(hDoc, STEPControl_AsIs);
 
                 // edit STEP header
-#if OCC_VERSION_HEX >= 0x060500
                 APIHeaderSection_MakeHeader makeHeader(writer.ChangeWriter().Model());
-#else
-                APIHeaderSection_MakeHeader makeHeader(writer.Writer().Model());
-#endif
+
                 Base::Reference<ParameterGrp> hGrp = App::GetApplication().GetUserParameter()
                     .GetGroup("BaseApp")->GetGroup("Preferences")->GetGroup("Mod/Part")->GetGroup("STEP");
 
diff --git a/src/Mod/MeshPart/App/MeshFlattening.cpp b/src/Mod/MeshPart/App/MeshFlattening.cpp
index d01f8496c1..e74534e73a 100644
--- a/src/Mod/MeshPart/App/MeshFlattening.cpp
+++ b/src/Mod/MeshPart/App/MeshFlattening.cpp
@@ -196,15 +196,9 @@ ColMat<double, 3> FaceUnwrapper::interpolateFlatFace(const TopoDS_Face& face)
     // extract xyz poles, knots, weights, degree
     const Handle(Geom_Surface) &_surface = BRep_Tool::Surface(face);
     const Handle(Geom_BSplineSurface) &_bspline = Handle(Geom_BSplineSurface)::DownCast(_surface);
-#if OCC_VERSION_HEX < 0x070000
-    TColStd_Array1OfReal _uknots(1, _bspline->NbUPoles() + _bspline->UDegree() + 1);
-    TColStd_Array1OfReal _vknots(1, _bspline->NbVPoles() + _bspline->VDegree() + 1);
-    _bspline->UKnotSequence(_uknots);
-    _bspline->VKnotSequence(_vknots);
-#else
+
     const TColStd_Array1OfReal &_uknots = _bspline->UKnotSequence();
     const TColStd_Array1OfReal &_vknots = _bspline->VKnotSequence();
-#endif
 
     Eigen::VectorXd weights;
     weights.resize(_bspline->NbUPoles() * _bspline->NbVPoles());
diff --git a/src/Mod/Part/App/AppPartPy.cpp b/src/Mod/Part/App/AppPartPy.cpp
index 5e961db381..8c7c9e09cb 100644
--- a/src/Mod/Part/App/AppPartPy.cpp
+++ b/src/Mod/Part/App/AppPartPy.cpp
@@ -1172,11 +1172,7 @@ private:
                 aPlane = new Geom_Plane(p, d);
             }
 
-            BRepBuilderAPI_MakeFace Face(aPlane, 0.0, length, 0.0, width
-#if OCC_VERSION_HEX >= 0x060502
-              , Precision::Confusion()
-#endif
-            );
+            BRepBuilderAPI_MakeFace Face(aPlane, 0.0, length, 0.0, width, Precision::Confusion() );
             return Py::asObject(new TopoShapeFacePy(new TopoShape((Face.Face()))));
         }
         catch (Standard_DomainError&) {
diff --git a/src/Mod/Part/App/Attacher.cpp b/src/Mod/Part/App/Attacher.cpp
index ede1359034..b7269a6c68 100644
--- a/src/Mod/Part/App/Attacher.cpp
+++ b/src/Mod/Part/App/Attacher.cpp
@@ -495,10 +495,8 @@ eRefType AttachEngine::getShapeType(const TopoDS_Shape& sh)
         case GeomAbs_BezierCurve:
         case GeomAbs_BSplineCurve:
         case GeomAbs_OtherCurve:
-#if OCC_VERSION_HEX >= 0x070000
         case GeomAbs_OffsetCurve:
-#endif
-            return rtCurve;
+        return rtCurve;
         }
     }break;
     case TopAbs_WIRE:
diff --git a/src/Mod/Part/App/BRepOffsetAPI_MakeOffsetFix.cpp b/src/Mod/Part/App/BRepOffsetAPI_MakeOffsetFix.cpp
index 2fb9e08bee..8c160c76c9 100644
--- a/src/Mod/Part/App/BRepOffsetAPI_MakeOffsetFix.cpp
+++ b/src/Mod/Part/App/BRepOffsetAPI_MakeOffsetFix.cpp
@@ -52,12 +52,7 @@ BRepOffsetAPI_MakeOffsetFix::BRepOffsetAPI_MakeOffsetFix()
 
 BRepOffsetAPI_MakeOffsetFix::BRepOffsetAPI_MakeOffsetFix(const GeomAbs_JoinType Join, const Standard_Boolean IsOpenResult)
 {
-#if OCC_VERSION_HEX >= 0x060900
     mkOffset.Init(Join, IsOpenResult);
-#else
-    (void)IsOpenResult;
-    mkOffset.Init(Join);
-#endif
 }
 
 BRepOffsetAPI_MakeOffsetFix::~BRepOffsetAPI_MakeOffsetFix()
diff --git a/src/Mod/Part/App/BRepOffsetAPI_MakePipeShellPyImp.cpp b/src/Mod/Part/App/BRepOffsetAPI_MakePipeShellPyImp.cpp
index 616adc3946..f09b9e6145 100644
--- a/src/Mod/Part/App/BRepOffsetAPI_MakePipeShellPyImp.cpp
+++ b/src/Mod/Part/App/BRepOffsetAPI_MakePipeShellPyImp.cpp
@@ -142,7 +142,6 @@ PyObject* BRepOffsetAPI_MakePipeShellPy::setSpineSupport(PyObject *args)
 
 PyObject* BRepOffsetAPI_MakePipeShellPy::setAuxiliarySpine(PyObject *args)
 {
-#if OCC_VERSION_HEX >= 0x060700
     PyObject *spine, *curv, *keep;
     if (!PyArg_ParseTuple(args, "O!O!O!",&Part::TopoShapePy::Type,&spine
                                         ,&PyBool_Type,&curv
@@ -178,31 +177,6 @@ PyObject* BRepOffsetAPI_MakePipeShellPy::setAuxiliarySpine(PyObject *args)
         PyErr_SetString(PartExceptionOCCError, e.GetMessageString());
         return nullptr;
     }
-#else
-    PyObject *spine, *curv, *keep;
-    if (!PyArg_ParseTuple(args, "O!O!O!",&Part::TopoShapePy::Type,&spine
-                                        ,&PyBool_Type,&curv
-                                        ,&PyBool_Type,&keep))
-        return 0;
-
-    try {
-        const TopoDS_Shape& s = static_cast<Part::TopoShapePy*>(spine)->getTopoShapePtr()->getShape();
-        if (s.IsNull() || s.ShapeType() != TopAbs_WIRE) {
-            PyErr_SetString(PyExc_TypeError, "spine is not a wire");
-            return 0;
-        }
-
-        this->getBRepOffsetAPI_MakePipeShellPtr()->SetMode(
-            TopoDS::Wire(s),
-            PyObject_IsTrue(curv) ? Standard_True : Standard_False,
-            PyObject_IsTrue(keep) ? Standard_True : Standard_False);
-        Py_Return;
-    }
-    catch (Standard_Failure& e) {
-        PyErr_SetString(PartExceptionOCCError, e.GetMessageString());
-        return 0;
-    }
-#endif
 }
 
 PyObject* BRepOffsetAPI_MakePipeShellPy::add(PyObject *args, PyObject *kwds)
@@ -440,14 +414,8 @@ PyObject* BRepOffsetAPI_MakePipeShellPy::setMaxDegree(PyObject *args)
         return nullptr;
 
     try {
-#if OCC_VERSION_HEX >= 0x060800
         this->getBRepOffsetAPI_MakePipeShellPtr()->SetMaxDegree(degree);
         Py_Return;
-#else
-        (void)args;
-        PyErr_SetString(PyExc_RuntimeError, "requires OCC >= 6.8");
-        return 0;
-#endif
     }
     catch (Standard_Failure& e) {
         PyErr_SetString(PartExceptionOCCError, e.GetMessageString());
@@ -462,14 +430,8 @@ PyObject* BRepOffsetAPI_MakePipeShellPy::setMaxSegments(PyObject *args)
         return nullptr;
 
     try {
-#if OCC_VERSION_HEX >= 0x060800
         this->getBRepOffsetAPI_MakePipeShellPtr()->SetMaxSegments(nbseg);
         Py_Return;
-#else
-        (void)args;
-        PyErr_SetString(PyExc_RuntimeError, "requires OCC >= 6.8");
-        return 0;
-#endif
     }
     catch (Standard_Failure& e) {
         PyErr_SetString(PartExceptionOCCError, e.GetMessageString());
@@ -484,13 +446,8 @@ PyObject* BRepOffsetAPI_MakePipeShellPy::setForceApproxC1(PyObject *args)
         return nullptr;
 
     try {
-#if OCC_VERSION_HEX >= 0x060700
         this->getBRepOffsetAPI_MakePipeShellPtr()->SetForceApproxC1(PyObject_IsTrue(obj) ? Standard_True : Standard_False);
         Py_Return;
-#else
-        PyErr_SetString(PyExc_RuntimeError, "requires OCC >= 6.7");
-        return 0;
-#endif
     }
     catch (Standard_Failure& e) {
         PyErr_SetString(PartExceptionOCCError, e.GetMessageString());
diff --git a/src/Mod/Part/App/FeaturePartFuse.cpp b/src/Mod/Part/App/FeaturePartFuse.cpp
index d98ecb760f..3e425309ae 100644
--- a/src/Mod/Part/App/FeaturePartFuse.cpp
+++ b/src/Mod/Part/App/FeaturePartFuse.cpp
@@ -112,34 +112,6 @@ App::DocumentObjectExecReturn *MultiFuse::execute(void)
     if (s.size() >= 2) {
         try {
             std::vector<ShapeHistory> history;
-#if OCC_VERSION_HEX <= 0x060800
-            TopoDS_Shape resShape = s.front();
-            if (resShape.IsNull())
-                throw NullShapeException("Input shape is null");
-            for (std::vector<TopoDS_Shape>::iterator it = s.begin()+1; it != s.end(); ++it) {
-                if (it->IsNull())
-                    throw NullShapeException("Input shape is null");
-
-                // Let's call algorithm computing a fuse operation:
-                BRepAlgoAPI_Fuse mkFuse(resShape, *it);
-                // Let's check if the fusion has been successful
-                if (!mkFuse.IsDone()) 
-                    throw BooleanException("Fusion failed");
-                resShape = mkFuse.Shape();
-
-                ShapeHistory hist1 = buildHistory(mkFuse, TopAbs_FACE, resShape, mkFuse.Shape1());
-                ShapeHistory hist2 = buildHistory(mkFuse, TopAbs_FACE, resShape, mkFuse.Shape2());
-                if (history.empty()) {
-                    history.push_back(hist1);
-                    history.push_back(hist2);
-                }
-                else {
-                    for (std::vector<ShapeHistory>::iterator jt = history.begin(); jt != history.end(); ++jt)
-                        *jt = joinHistory(*jt, hist1);
-                    history.push_back(hist2);
-                }
-            }
-#else
             BRepAlgoAPI_Fuse mkFuse;
             TopTools_ListOfShape shapeArguments,shapeTools;
             const TopoDS_Shape& shape = s.front();
@@ -163,7 +135,6 @@ App::DocumentObjectExecReturn *MultiFuse::execute(void)
             for (std::vector<TopoDS_Shape>::iterator it = s.begin(); it != s.end(); ++it) {
                 history.push_back(buildHistory(mkFuse, TopAbs_FACE, resShape, *it));
             }
-#endif
             if (resShape.IsNull())
                 throw Base::RuntimeError("Resulting shape is null");
 
diff --git a/src/Mod/Part/App/FeaturePartSection.cpp b/src/Mod/Part/App/FeaturePartSection.cpp
index da4e47855b..cd5de1f1ff 100644
--- a/src/Mod/Part/App/FeaturePartSection.cpp
+++ b/src/Mod/Part/App/FeaturePartSection.cpp
@@ -51,9 +51,7 @@ short Section::mustExecute() const
 BRepAlgoAPI_BooleanOperation* Section::makeOperation(const TopoDS_Shape& base, const TopoDS_Shape& tool) const
 {
     // Let's call algorithm computing a section operation:
-#if OCC_VERSION_HEX < 0x060900
-    return new BRepAlgoAPI_Section(base, tool);
-#else
+
     bool approx = Approximation.getValue();
     std::unique_ptr<BRepAlgoAPI_Section> mkSection(new BRepAlgoAPI_Section());
     mkSection->Init1(base);
@@ -63,5 +61,4 @@ BRepAlgoAPI_BooleanOperation* Section::makeOperation(const TopoDS_Shape& base, c
     if (!mkSection->IsDone())
         throw Base::RuntimeError("Section failed");
     return mkSection.release();
-#endif
 }
diff --git a/src/Mod/Part/App/Geom2d/Geometry2dPyImp.cpp b/src/Mod/Part/App/Geom2d/Geometry2dPyImp.cpp
index 5b7c9523d1..b8bc44e237 100644
--- a/src/Mod/Part/App/Geom2d/Geometry2dPyImp.cpp
+++ b/src/Mod/Part/App/Geom2d/Geometry2dPyImp.cpp
@@ -143,13 +143,7 @@ PyObject* Geometry2dPy::transform(PyObject *args)
     double a23 = static_cast<double>(Py::Float(list.getItem(5)));
 
     gp_Trsf mat;
-    mat.SetValues(a11, a12, 0, a13,
-                  a21, a22, 0, a23,
-                  0  ,   0, 1,   0
-#if OCC_VERSION_HEX < 0x060800
-                  , 0.00001,0.00001
-#endif
-                ); //precision was removed in OCCT CR0025194
+    mat.SetValues(a11, a12, 0, a13, a21, a22, 0, a23, 0, 0, 1, 0);
     gp_Trsf2d trf(mat);
 
     getGeometry2dPtr()->handle()->Transform(trf);
diff --git a/src/Mod/Part/App/Geometry.cpp b/src/Mod/Part/App/Geometry.cpp
index 6ebcf01b0a..346968974e 100644
--- a/src/Mod/Part/App/Geometry.cpp
+++ b/src/Mod/Part/App/Geometry.cpp
@@ -462,11 +462,7 @@ void Geometry::transform(const Base::Matrix4D& mat)
     gp_Trsf trf;
     trf.SetValues(mat[0][0],mat[0][1],mat[0][2],mat[0][3],
                 mat[1][0],mat[1][1],mat[1][2],mat[1][3],
-                mat[2][0],mat[2][1],mat[2][2],mat[2][3]
-#if OCC_VERSION_HEX < 0x060800
-                , 0.00001,0.00001
-#endif
-                ); //precision was removed in OCCT CR0025194
+                mat[2][0],mat[2][1],mat[2][2],mat[2][3]);
     handle()->Transform(trf);
 }
 
@@ -2138,11 +2134,8 @@ void GeomArcOfConic::setXAxisDir(const Base::Vector3d& newdir)
     Handle(Geom_TrimmedCurve) curve =  Handle(Geom_TrimmedCurve)::DownCast(handle());
     Handle(Geom_Conic) c = Handle(Geom_Conic)::DownCast( curve->BasisCurve() );
     assert(!c.IsNull());
-#if OCC_VERSION_HEX >= 0x060504
+
     if (newdir.Sqr() < Precision::SquareConfusion())
-#else
-    if (newdir.Length() < Precision::Confusion())
-#endif
         return;//zero vector was passed. Keep the old orientation.
 
     try {
@@ -2722,11 +2715,7 @@ Base::Vector3d GeomEllipse::getMajorAxisDir() const
  */
 void GeomEllipse::setMajorAxisDir(Base::Vector3d newdir)
 {
-#if OCC_VERSION_HEX >= 0x060504
     if (newdir.Sqr() < Precision::SquareConfusion())
-#else
-    if (newdir.Length() < Precision::Confusion())
-#endif
         return;//zero vector was passed. Keep the old orientation.
     try {
         gp_Ax2 pos = myCurve->Position();
@@ -2941,11 +2930,7 @@ void GeomArcOfEllipse::setMajorAxisDir(Base::Vector3d newdir)
 {
     Handle(Geom_Ellipse) c = Handle(Geom_Ellipse)::DownCast( myCurve->BasisCurve() );
     assert(!c.IsNull());
-#if OCC_VERSION_HEX >= 0x060504
     if (newdir.Sqr() < Precision::SquareConfusion())
-#else
-    if (newdir.Length() < Precision::Confusion())
-#endif
         return;//zero vector was passed. Keep the old orientation.
     try {
         gp_Ax2 pos = c->Position();
@@ -3379,11 +3364,7 @@ void GeomArcOfHyperbola::setMajorAxisDir(Base::Vector3d newdir)
 {
     Handle(Geom_Hyperbola) c = Handle(Geom_Hyperbola)::DownCast( myCurve->BasisCurve() );
     assert(!c.IsNull());
-    #if OCC_VERSION_HEX >= 0x060504
     if (newdir.Sqr() < Precision::SquareConfusion())
-    #else
-    if (newdir.Length() < Precision::Confusion())
-    #endif
         return;//zero vector was passed. Keep the old orientation.
 
     try {
@@ -4239,11 +4220,7 @@ TopoDS_Shape GeomSurface::toShape() const
     Handle(Geom_Surface) s = Handle(Geom_Surface)::DownCast(handle());
     Standard_Real u1,u2,v1,v2;
     s->Bounds(u1,u2,v1,v2);
-    BRepBuilderAPI_MakeFace mkBuilder(s, u1, u2, v1, v2
-#if OCC_VERSION_HEX >= 0x060502
-      , Precision::Confusion()
-#endif
-      );
+    BRepBuilderAPI_MakeFace mkBuilder(s, u1, u2, v1, v2, Precision::Confusion() );
     return mkBuilder.Shape();
 }
 
@@ -4255,7 +4232,6 @@ bool GeomSurface::tangentU(double u, double v, gp_Dir& dirU) const
         prop.TangentU(dirU);
         return true;
     }
-
     return false;
 }
 
@@ -5555,13 +5531,11 @@ std::unique_ptr<GeomCurve> makeFromCurveAdaptor(const Adaptor3d_Curve& adapt)
             geoCurve.reset(new GeomBSplineCurve(adapt.BSpline()));
             break;
         }
-#if OCC_VERSION_HEX >= 0x070000
     case GeomAbs_OffsetCurve:
         {
             geoCurve.reset(new GeomOffsetCurve(adapt.OffsetCurve()));
             break;
         }
-#endif
     case GeomAbs_OtherCurve:
     default:
         break;
diff --git a/src/Mod/Part/App/GeometrySurfacePyImp.cpp b/src/Mod/Part/App/GeometrySurfacePyImp.cpp
index 8b4ffcf53b..f513033eca 100644
--- a/src/Mod/Part/App/GeometrySurfacePyImp.cpp
+++ b/src/Mod/Part/App/GeometrySurfacePyImp.cpp
@@ -136,11 +136,7 @@ PyObject* GeometrySurfacePy::toShape(PyObject *args)
             s->Bounds(u1,u2,v1,v2);
             if (!PyArg_ParseTuple(args, "|dddd", &u1,&u2,&v1,&v2))
                 return nullptr;
-            BRepBuilderAPI_MakeFace mkBuilder(s, u1, u2, v1, v2
-#if OCC_VERSION_HEX >= 0x060502
-              , Precision::Confusion()
-#endif
-            );
+            BRepBuilderAPI_MakeFace mkBuilder(s, u1, u2, v1, v2, Precision::Confusion() );
             TopoDS_Shape sh = mkBuilder.Shape();
             return new TopoShapeFacePy(new TopoShape(sh));
         }
diff --git a/src/Mod/Part/App/ImportStep.cpp b/src/Mod/Part/App/ImportStep.cpp
index c8a7fb5f12..5800270ef5 100644
--- a/src/Mod/Part/App/ImportStep.cpp
+++ b/src/Mod/Part/App/ImportStep.cpp
@@ -243,222 +243,16 @@ int Part::ImportStepParts(App::Document *pcDoc, const char* Name)
     return 0;
 }
 
-#if OCC_VERSION_HEX < 0x070000
-static void findStyledSR (const Handle(StepVisual_StyledItem) &style,
-                          Handle(StepShape_ShapeRepresentation)& aSR)
-{
-    // search Shape Representation for component styled item
-    for (Standard_Integer j=1; j <= style->NbStyles(); j++) {
-        Handle(StepVisual_PresentationStyleByContext) PSA =
-            Handle(StepVisual_PresentationStyleByContext)::DownCast(style->StylesValue ( j ));
-        if (PSA.IsNull())
-            continue;
-        StepVisual_StyleContextSelect aStyleCntxSlct = PSA->StyleContext();
-        Handle(StepShape_ShapeRepresentation) aCurrentSR =
-            Handle(StepShape_ShapeRepresentation)::DownCast(aStyleCntxSlct.Representation());
-        if (aCurrentSR.IsNull())
-            continue;
-        aSR = aCurrentSR;
-            break;
-    }
-}
-#endif
 
 bool Part::ReadColors (const Handle(XSControl_WorkSession) &WS, std::map<int, Quantity_Color>& hash_col)
 {
-#if OCC_VERSION_HEX >= 0x070000
     (void)WS;
     (void)hash_col;
     return Standard_False;
-#else
-    STEPConstruct_Styles Styles (WS);
-    if (!Styles.LoadStyles()) {
-#ifdef FC_DEBUG
-        std::cout << "Warning: no styles are found in the model" << std::endl;
-#endif
-        return Standard_False;
-    }
-    // searching for invisible items in the model
-    Handle(TColStd_HSequenceOfTransient) aHSeqOfInvisStyle = new TColStd_HSequenceOfTransient;
-    Styles.LoadInvisStyles( aHSeqOfInvisStyle );
-
-    // parse and search for color attributes
-    Standard_Integer nb = Styles.NbStyles();
-    for (Standard_Integer i=1; i <= nb; i++) {
-        Handle(StepVisual_StyledItem) style = Styles.Style (i);
-        if (style.IsNull()) continue;
-
-        Standard_Boolean IsVisible = Standard_True;
-        // check the visibility of styled item.
-        for (Standard_Integer si = 1; si <= aHSeqOfInvisStyle->Length(); si++) {
-            if (style != aHSeqOfInvisStyle->Value(si))
-                continue;
-            // found that current style is invisible.
-#ifdef FC_DEBUG
-            std::cout << "Warning: item No " << i << "(" << style->Item()->DynamicType()->Name() << ") is invisible" << std::endl;
-#endif
-            IsVisible = Standard_False;
-            break;
-        }
-
-        Handle(StepVisual_Colour) SurfCol, BoundCol, CurveCol;
-        // check if it is component style
-        Standard_Boolean IsComponent = Standard_False;
-        if (!Styles.GetColors (style, SurfCol, BoundCol, CurveCol, IsComponent) && IsVisible)
-            continue;
-
-        // find shape
-        TopoDS_Shape S = STEPConstruct::FindShape(Styles.TransientProcess(), style->Item());
-        //TopAbs_ShapeEnum type = S.ShapeType();
-        Standard_Boolean isSkipSHUOstyle = Standard_False;
-        // take shape with real location.
-        while (IsComponent) {
-            // take SR of NAUO
-            Handle(StepShape_ShapeRepresentation) aSR;
-            findStyledSR(style, aSR);
-            // search for SR along model
-            if (aSR.IsNull())
-                break;
-//          Handle(Interface_InterfaceModel) Model = WS->Model();
-            Handle(XSControl_TransferReader) TR = WS->TransferReader();
-            Handle(Transfer_TransientProcess) TP = TR->TransientProcess();
-            Interface_EntityIterator subs = WS->HGraph()->Graph().Sharings( aSR );
-            Handle(StepShape_ShapeDefinitionRepresentation) aSDR;
-            for (subs.Start(); subs.More(); subs.Next()) {
-                aSDR = Handle(StepShape_ShapeDefinitionRepresentation)::DownCast(subs.Value());
-                if (aSDR.IsNull())
-                    continue;
-                StepRepr_RepresentedDefinition aPDSselect = aSDR->Definition();
-                Handle(StepRepr_ProductDefinitionShape) PDS =
-                    Handle(StepRepr_ProductDefinitionShape)::DownCast(aPDSselect.PropertyDefinition());
-                if (PDS.IsNull())
-                    continue;
-                StepRepr_CharacterizedDefinition aCharDef = PDS->Definition();
-
-                Handle(StepRepr_AssemblyComponentUsage) ACU =
-                    Handle(StepRepr_AssemblyComponentUsage)::DownCast(aCharDef.ProductDefinitionRelationship());
-                // PTV 10.02.2003 skip styled item that refer to SHUO
-                if (ACU->IsKind(STANDARD_TYPE(StepRepr_SpecifiedHigherUsageOccurrence))) {
-                    isSkipSHUOstyle = Standard_True;
-                    break;
-                }
-                Handle(StepRepr_NextAssemblyUsageOccurrence) NAUO =
-                    Handle(StepRepr_NextAssemblyUsageOccurrence)::DownCast(ACU);
-                if (NAUO.IsNull())
-                    continue;
-
-                TopoDS_Shape aSh;
-                // PTV 10.02.2003 to find component of assembly CORRECTLY
-                STEPConstruct_Tool Tool( WS );
-//              Handle(Transfer_Binder) binder = TP->Find(NAUO);
-//              if (binder.IsNull() || ! binder->HasResult())
-//                  continue;
-//              aSh = TransferBRep::ShapeResult ( TP, binder );
-                if (!aSh.IsNull()) {
-                    S = aSh;
-                    break;
-                }
-            }
-            break;
-        }
-        if (isSkipSHUOstyle)
-            continue; // skip styled item which refer to SHUO
-
-        if ( S.IsNull() ) {
-#ifdef FC_DEBUG
-            std::cout << "Warning: item No " << i << "(" << style->Item()->DynamicType()->Name() << ") is not mapped to shape" << std::endl;
-#endif
-            continue;
-        }
-
-        if (!SurfCol.IsNull()) {
-            Quantity_Color col;
-            Styles.DecodeColor (SurfCol, col);
-            //Base::Console().Message("%d: (%.2f,%.2f,%.2f)\n",col.Name(),col.Red(),col.Green(),col.Blue());
-            hash_col[S.HashCode(INT_MAX)] = col;
-        }
-        if (!BoundCol.IsNull()) {
-            Quantity_Color col;
-            Styles.DecodeColor (BoundCol, col);
-            //Base::Console().Message("%d: (%.2f,%.2f,%.2f)\n",col.Name(),col.Red(),col.Green(),col.Blue());
-            hash_col[S.HashCode(INT_MAX)] = col;
-        }
-        if (!CurveCol.IsNull()) {
-            Quantity_Color col;
-            Styles.DecodeColor (CurveCol, col);
-            //Base::Console().Message("%d: (%.2f,%.2f,%.2f)\n",col.Name(),col.Red(),col.Green(),col.Blue());
-            hash_col[S.HashCode(INT_MAX)] = col;
-        }
-        if (!IsVisible) {
-            // sets the invisibility for shape.
-        }
-    }
-
-    return Standard_True;
-#endif
 }
 
 bool Part::ReadNames (const Handle(XSControl_WorkSession) &WS)
 {
-#if OCC_VERSION_HEX >= 0x070000
     (void)WS;
     return Standard_False;
-#else
-    // get starting data
-    Handle(Interface_InterfaceModel) Model = WS->Model();
-    Handle(XSControl_TransferReader) TR = WS->TransferReader();
-    Handle(Transfer_TransientProcess) TP = TR->TransientProcess();
-
-    STEPConstruct_Tool Tool ( WS );
-
-    // iterate on model to find all SDRs and CDSRs
-    Standard_Integer nb = Model->NbEntities();
-    Handle(Standard_Type) tNAUO = STANDARD_TYPE(StepRepr_NextAssemblyUsageOccurrence);
-    Handle(Standard_Type) tPD  = STANDARD_TYPE(StepBasic_ProductDefinition);
-    Handle(TCollection_HAsciiString) name;
-    for (Standard_Integer i = 1; i <= nb; i++) {
-        Handle(Standard_Transient) enti = Model->Value(i);
-
-        // get description of NAUO
-        if (enti->DynamicType() == tNAUO) {
-            Handle(StepRepr_NextAssemblyUsageOccurrence) NAUO =
-                Handle(StepRepr_NextAssemblyUsageOccurrence)::DownCast(enti);
-            if (NAUO.IsNull()) continue;
-            Interface_EntityIterator subs = WS->Graph().Sharings(NAUO);
-            for (subs.Start(); subs.More(); subs.Next()) {
-                Handle(StepRepr_ProductDefinitionShape) PDS =
-                    Handle(StepRepr_ProductDefinitionShape)::DownCast(subs.Value());
-                if (PDS.IsNull()) continue;
-                Handle(StepBasic_ProductDefinitionRelationship) PDR = PDS->Definition().ProductDefinitionRelationship();
-                if (PDR.IsNull()) continue;
-                if (PDR->HasDescription() &&
-                    PDR->Description()->Length() >0 ) name = PDR->Description();
-                else if (PDR->Name()->Length() >0) name = PDR->Name();
-                else name = PDR->Id();
-            }
-
-            // find proper label
-            TCollection_ExtendedString str ( name->String() );
-            Base::Console().Message("Name: %s\n",name->String().ToCString());
-        }
-
-        // for PD get name of associated product
-        if (enti->DynamicType() == tPD) {
-            Handle(StepBasic_ProductDefinition) PD =
-                Handle(StepBasic_ProductDefinition)::DownCast(enti);
-            if (PD.IsNull()) continue;
-            Handle(StepBasic_Product) Prod = PD->Formation()->OfProduct();
-            if (Prod->Name()->UsefullLength()>0) name = Prod->Name();
-            else name = Prod->Id();
-
-            TCollection_ExtendedString str ( name->String() );
-            Base::Console().Message("Name: %s\n",name->String().ToCString());
-        }
-        // set a name to the document
-        //TCollection_ExtendedString str ( name->String() );
-        //TDataStd_Name::Set ( L, str );
-    }
-
-    return Standard_True;
-#endif
 }
diff --git a/src/Mod/Part/App/OCCError.h b/src/Mod/Part/App/OCCError.h
index 19e8208179..fecd402149 100644
--- a/src/Mod/Part/App/OCCError.h
+++ b/src/Mod/Part/App/OCCError.h
@@ -27,9 +27,7 @@
 # include <Standard_Failure.hxx>
 # include <Standard_AbortiveTransaction.hxx>
 # include <Standard_ConstructionError.hxx>
-# if OCC_VERSION_HEX >= 0x060500
 # include <Standard_DefineException.hxx>
-# endif
 # include <Standard_DimensionError.hxx>
 # include <Standard_DimensionMismatch.hxx>
 # include <Standard_DivideByZero.hxx>
diff --git a/src/Mod/Part/App/OpenCascadeAll.h b/src/Mod/Part/App/OpenCascadeAll.h
index 5babfe44b9..b4b8afc233 100644
--- a/src/Mod/Part/App/OpenCascadeAll.h
+++ b/src/Mod/Part/App/OpenCascadeAll.h
@@ -184,10 +184,7 @@
 #include <ShapeFix_ShapeTolerance.hxx>
 
 #include <BRepOffset_MakeOffset.hxx>
-
-#if OCC_VERSION_HEX >= 0x060600
 #include <BRepClass3d.hxx>
-#endif
 #if OCC_VERSION_HEX < 0x070600
 #include <Adaptor3d_HCurve.hxx>
 #include <Adaptor3d_HCurveOnSurface.hxx>
@@ -231,15 +228,11 @@
 #include <BRepLProp_SurfaceTool.hxx>
 #include <BRepGProp_Face.hxx>
 #include <BRepClass_FaceClassifier.hxx>
-#if OCC_VERSION_HEX >= 0x060600
 #include <BRepClass3d.hxx>
-#endif
 #include <BRepClass3d_SolidClassifier.hxx>
 #include <BRepExtrema_DistShapeShape.hxx>
 #include <BRepExtrema_MapOfIntegerPackedMapOfInteger.hxx>
-#if OCC_VERSION_HEX >= 0x060801
 #include <BRepExtrema_ShapeProximity.hxx>
-#endif
 #include <BRepFeat_SplitShape.hxx>
 #include <BRepFeat_MakePrism.hxx>
 #include <BRepFilletAPI_MakeChamfer.hxx>
@@ -507,18 +500,14 @@
 #include <ShapeAnalysis_FreeBoundsProperties.hxx>
 #include <ShapeAnalysis_FreeBoundData.hxx>
 
-#if OCC_VERSION_HEX >= 0x060600
 # include <BOPAlgo_ArgumentAnalyzer.hxx>
 # include <BOPAlgo_ListOfCheckResult.hxx>
-#endif
 
 #if OCC_VERSION_HEX >= 0x070300
 # include <BRepAlgoAPI_Defeaturing.hxx>
 #endif
 
-#if OCC_VERSION_HEX >= 0x060800
 #include <OSD_OpenFile.hxx>
-#endif
 
 #endif // __OpenCascadeAll__
 
diff --git a/src/Mod/Part/App/PartFeature.cpp b/src/Mod/Part/App/PartFeature.cpp
index 0dcb2883c4..475f4924e8 100644
--- a/src/Mod/Part/App/PartFeature.cpp
+++ b/src/Mod/Part/App/PartFeature.cpp
@@ -188,12 +188,10 @@ App::DocumentObject *Feature::getSubObject(const char *subname,
         // instance or do simply nothing. For now the error message is degraded to a log message.
         std::ostringstream str;
         Standard_CString msg = e.GetMessageString();
-#if OCC_VERSION_HEX >= 0x070000
+
         // Avoid name mangling
         str << e.DynamicType()->get_type_name() << " ";
-#else
-        str << typeid(e).name() << " ";
-#endif
+
         if (msg) {str << msg;}
         else     {str << "No OCCT Exception Message";}
         str << ": " << getFullName();
diff --git a/src/Mod/Part/App/PrimitiveFeature.cpp b/src/Mod/Part/App/PrimitiveFeature.cpp
index de04a851d6..ac057e79a3 100644
--- a/src/Mod/Part/App/PrimitiveFeature.cpp
+++ b/src/Mod/Part/App/PrimitiveFeature.cpp
@@ -324,11 +324,7 @@ App::DocumentObjectExecReturn *Plane::execute(void)
     gp_Pnt pnt(0.0,0.0,0.0);
     gp_Dir dir(0.0,0.0,1.0);
     Handle(Geom_Plane) aPlane = new Geom_Plane(pnt, dir);
-    BRepBuilderAPI_MakeFace mkFace(aPlane, 0.0, L, 0.0, W
-#if OCC_VERSION_HEX >= 0x060502
-      , Precision::Confusion()
-#endif
-    );
+    BRepBuilderAPI_MakeFace mkFace(aPlane, 0.0, L, 0.0, W, Precision::Confusion());
 
     const char *error=nullptr;
     switch (mkFace.Error())
@@ -346,11 +342,6 @@ App::DocumentObjectExecReturn *Plane::execute(void)
     case BRepBuilderAPI_ParametersOutOfRange:
         error = "parameters out of range";
         break;
-#if OCC_VERSION_HEX < 0x060500
-    case BRepBuilderAPI_SurfaceNotC2:
-        error = "surface not C2";
-        break;
-#endif
     default:
         error = "unknown error";
         break;
diff --git a/src/Mod/Part/App/PropertyTopoShape.cpp b/src/Mod/Part/App/PropertyTopoShape.cpp
index 38513236de..61664f045f 100644
--- a/src/Mod/Part/App/PropertyTopoShape.cpp
+++ b/src/Mod/Part/App/PropertyTopoShape.cpp
@@ -43,9 +43,7 @@
 # include <gp_GTrsf.hxx>
 # include <gp_Trsf.hxx>
 
-#if OCC_VERSION_HEX >= 0x060800
 # include <OSD_OpenFile.hxx>
-#endif
 
 #endif // _PreComp_
 
@@ -248,11 +246,8 @@ void PropertyPartShape::Restore(Base::XMLReader &reader)
 static Standard_Boolean  BRepTools_Write(const TopoDS_Shape& Sh, const Standard_CString File)
 {
   std::ofstream os;
-#if OCC_VERSION_HEX >= 0x060800
   OSD_OpenStream(os, File, std::ios::out);
-#else
-  os.open(File, std::ios::out);
-#endif
+
   if (!os.rdbuf()->is_open())
       return Standard_False;
 
diff --git a/src/Mod/Part/App/Tools.cpp b/src/Mod/Part/App/Tools.cpp
index c29ead7a6d..514426652e 100644
--- a/src/Mod/Part/App/Tools.cpp
+++ b/src/Mod/Part/App/Tools.cpp
@@ -632,11 +632,7 @@ Handle (Poly_Triangulation) Part::Tools::triangulationOfFace(const TopoDS_Face&
     selectRange(v1, v2);
 
     Handle(Geom_Surface) surface = BRep_Tool::Surface(face);
-    BRepBuilderAPI_MakeFace mkBuilder(surface, u1, u2, v1, v2
-#if OCC_VERSION_HEX >= 0x060502
-      , Precision::Confusion()
-#endif
-    );
+    BRepBuilderAPI_MakeFace mkBuilder(surface, u1, u2, v1, v2, Precision::Confusion() );
 
     TopoDS_Shape shape = mkBuilder.Shape();
     shape.Location(loc);
diff --git a/src/Mod/Part/App/TopoShape.cpp b/src/Mod/Part/App/TopoShape.cpp
index b556326cc5..a9c07c0197 100644
--- a/src/Mod/Part/App/TopoShape.cpp
+++ b/src/Mod/Part/App/TopoShape.cpp
@@ -176,10 +176,8 @@
 # include <BRepAlgo_Fuse.hxx>
 #endif
 
-#if OCC_VERSION_HEX >= 0x060600
 # include <BOPAlgo_ArgumentAnalyzer.hxx>
 # include <BOPAlgo_ListOfCheckResult.hxx>
-#endif
 
 #if OCC_VERSION_HEX >= 0x070300
 # include <BRepAlgoAPI_Defeaturing.hxx>
@@ -239,10 +237,6 @@ const char* BRepBuilderAPI_FaceErrorText(BRepBuilderAPI_FaceError et)
         return "Curve projection failed";
     case BRepBuilderAPI_ParametersOutOfRange:
         return "Parameters out of range";
-#if OCC_VERSION_HEX < 0x060500
-    case BRepBuilderAPI_SurfaceNotC2:
-        return "Surface not C2-continuous";
-#endif
     default:
         return "Unknown creation error";
     }
@@ -627,16 +621,11 @@ void TopoShape::convertTogpTrsf(const Base::Matrix4D& mtrx, gp_Trsf& trsf)
 {
     trsf.SetValues(mtrx[0][0],mtrx[0][1],mtrx[0][2],mtrx[0][3],
                    mtrx[1][0],mtrx[1][1],mtrx[1][2],mtrx[1][3],
-                   mtrx[2][0],mtrx[2][1],mtrx[2][2],mtrx[2][3]
-#if OCC_VERSION_HEX < 0x060800
-                  , 0.00001,0.00001
-#endif
-                ); //precision was removed in OCCT CR0025194
+                   mtrx[2][0],mtrx[2][1],mtrx[2][2],mtrx[2][3]);
 }
 
 void TopoShape::convertToMatrix(const gp_Trsf& trsf, Base::Matrix4D& mtrx)
 {
-#if OCC_VERSION_HEX >= 0x070000
     // https://www.opencascade.com/doc/occt-7.0.0/refman/html/classgp___trsf.html
     // VectorialPart() already includes the scale factor
     gp_Mat m = trsf.VectorialPart();
@@ -659,29 +648,6 @@ void TopoShape::convertToMatrix(const gp_Trsf& trsf, Base::Matrix4D& mtrx)
     mtrx[0][3] = p.X();
     mtrx[1][3] = p.Y();
     mtrx[2][3] = p.Z();
-#else
-    gp_Mat m = trsf._CSFDB_Getgp_Trsfmatrix();
-    gp_XYZ p = trsf._CSFDB_Getgp_Trsfloc();
-    Standard_Real scale = trsf._CSFDB_Getgp_Trsfscale();
-
-    // set Rotation matrix
-    mtrx[0][0] = scale * m._CSFDB_Getgp_Matmatrix(0,0);
-    mtrx[0][1] = scale * m._CSFDB_Getgp_Matmatrix(0,1);
-    mtrx[0][2] = scale * m._CSFDB_Getgp_Matmatrix(0,2);
-
-    mtrx[1][0] = scale * m._CSFDB_Getgp_Matmatrix(1,0);
-    mtrx[1][1] = scale * m._CSFDB_Getgp_Matmatrix(1,1);
-    mtrx[1][2] = scale * m._CSFDB_Getgp_Matmatrix(1,2);
-
-    mtrx[2][0] = scale * m._CSFDB_Getgp_Matmatrix(2,0);
-    mtrx[2][1] = scale * m._CSFDB_Getgp_Matmatrix(2,1);
-    mtrx[2][2] = scale * m._CSFDB_Getgp_Matmatrix(2,2);
-
-    // set pos vector
-    mtrx[0][3] = p._CSFDB_Getgp_XYZx();
-    mtrx[1][3] = p._CSFDB_Getgp_XYZy();
-    mtrx[2][3] = p._CSFDB_Getgp_XYZz();
-#endif
 }
 
 Base::Matrix4D TopoShape::convert(const gp_Trsf& trsf) {
@@ -872,7 +838,7 @@ void TopoShape::importBrep(const char *FileName)
         // read brep-file
         BRep_Builder aBuilder;
         TopoDS_Shape aShape;
-#if OCC_VERSION_HEX >= 0x060300 && OCC_VERSION_HEX < 0x070500
+#if OCC_VERSION_HEX < 0x070500
         Handle(Message_ProgressIndicator) pi = new ProgressIndicator(100);
         pi->NewScope(100, "Reading BREP file...");
         pi->Show();
@@ -894,7 +860,7 @@ void TopoShape::importBrep(std::istream& str, int indicator)
         // read brep-file
         BRep_Builder aBuilder;
         TopoDS_Shape aShape;
-#if OCC_VERSION_HEX >= 0x060300 && OCC_VERSION_HEX < 0x070500
+#if OCC_VERSION_HEX < 0x070500
         if (indicator) {
             Handle(Message_ProgressIndicator) pi = new ProgressIndicator(100);
             pi->NewScope(100, "Reading BREP file...");
@@ -1095,18 +1061,11 @@ void TopoShape::dump(std::ostream& out) const
 void TopoShape::exportStl(const char *filename, double deflection) const
 {
     StlAPI_Writer writer;
-#if OCC_VERSION_HEX < 0x060801
-    if (deflection > 0) {
-        writer.RelativeMode() = false;
-        writer.SetDeflection(deflection);
-    }
-#else
     BRepMesh_IncrementalMesh aMesh(this->_Shape, deflection,
                                    /*isRelative*/ Standard_False,
                                    /*theAngDeflection*/
                                    defaultAngularDeflection(deflection),
                                    /*isInParallel*/ true);
-#endif
     writer.Write(this->_Shape,encodeFilename(filename).c_str());
 }
 
@@ -1652,31 +1611,23 @@ bool TopoShape::analyze(bool runBopCheck, std::ostream& str) const
             return false; // errors detected
         }
         else if (runBopCheck) {
-            // Copied from TaskCheckGeometryResults::goBOPSingleCheck
-#if OCC_VERSION_HEX >= 0x060600
+
             TopoDS_Shape BOPCopy = BRepBuilderAPI_Copy(this->_Shape).Shape();
             BOPAlgo_ArgumentAnalyzer BOPCheck;
-          //   BOPCheck.StopOnFirstFaulty() = true; //this doesn't run any faster but gives us less results.
             BOPCheck.SetShape1(BOPCopy);
             //all settings are false by default. so only turn on what we want.
             BOPCheck.ArgumentTypeMode() = true;
             BOPCheck.SelfInterMode() = true;
             BOPCheck.SmallEdgeMode() = true;
             BOPCheck.RebuildFaceMode() = true;
-#if OCC_VERSION_HEX >= 0x060700
             BOPCheck.ContinuityMode() = true;
-#endif
-#if OCC_VERSION_HEX >= 0x060900
             BOPCheck.SetParallelMode(true); //this doesn't help for speed right now(occt 6.9.1).
             BOPCheck.SetRunParallel(true); //performance boost, use all available cores
             BOPCheck.TangentMode() = true; //these 4 new tests add about 5% processing time.
             BOPCheck.MergeVertexMode() = true;
             BOPCheck.CurveOnSurfaceMode() = true;
             BOPCheck.MergeEdgeMode() = true;
-#endif
-
             BOPCheck.Perform();
-
             if (!BOPCheck.HasFaulty())
                 return true;
 
@@ -1688,25 +1639,17 @@ bool TopoShape::analyze(bool runBopCheck, std::ostream& str) const
             for (; BOPResultsIt.More(); BOPResultsIt.Next()) {
                 const BOPAlgo_CheckResult &current = BOPResultsIt.Value();
 
-#if OCC_VERSION_HEX < 0x070000
-                const BOPCol_ListOfShape &faultyShapes1 = current.GetFaultyShapes1();
-                BOPCol_ListIteratorOfListOfShape faultyShapes1It(faultyShapes1);
-#else
                 const TopTools_ListOfShape &faultyShapes1 = current.GetFaultyShapes1();
                 TopTools_ListIteratorOfListOfShape faultyShapes1It(faultyShapes1);
-#endif
                 for (;faultyShapes1It.More(); faultyShapes1It.Next()) {
                     const TopoDS_Shape &faultyShape = faultyShapes1It.Value();
                     str << "Error in " << shapeEnumToString[faultyShape.ShapeType()] << ": ";
                     str << bopEnumToString[current.GetCheckStatus()] << std::endl;
                 }
             }
-
             return false;
-#endif // 0x060600
         }
     }
-
     return true;
 }
 
diff --git a/src/Mod/Part/App/TopoShapeEdgePyImp.cpp b/src/Mod/Part/App/TopoShapeEdgePyImp.cpp
index 981dd503b7..1018b70242 100644
--- a/src/Mod/Part/App/TopoShapeEdgePyImp.cpp
+++ b/src/Mod/Part/App/TopoShapeEdgePyImp.cpp
@@ -871,7 +871,6 @@ Py::Object TopoShapeEdgePy::getCurve() const
             curve = new BSplineCurvePy(bspline);
             break;
         }
-#if OCC_VERSION_HEX >= 0x070000
     case GeomAbs_OffsetCurve:
         {
             Standard_Real first, last;
@@ -886,7 +885,6 @@ Py::Object TopoShapeEdgePy::getCurve() const
                 throw Py::RuntimeError("Failed to convert to offset curve");
             }
         }
-#endif
     case GeomAbs_OtherCurve:
         break;
     }
diff --git a/src/Mod/Part/App/TopoShapeFacePyImp.cpp b/src/Mod/Part/App/TopoShapeFacePyImp.cpp
index f4a62e7544..ac5ed87690 100644
--- a/src/Mod/Part/App/TopoShapeFacePyImp.cpp
+++ b/src/Mod/Part/App/TopoShapeFacePyImp.cpp
@@ -233,11 +233,7 @@ int TopoShapeFacePy::PyInit(PyObject* args, PyObject* /*kwd*/)
                 return -1;
             }
 
-            BRepBuilderAPI_MakeFace mkFace(S
-#if OCC_VERSION_HEX >= 0x060502
-              , Precision::Confusion()
-#endif
-            );
+            BRepBuilderAPI_MakeFace mkFace(S, Precision::Confusion());
             if (bound) {
                 Py::List list(bound);
                 for (Py::List::iterator it = list.begin(); it != list.end(); ++it) {
@@ -301,11 +297,6 @@ int TopoShapeFacePy::PyInit(PyObject* args, PyObject* /*kwd*/)
                     case BRepBuilderAPI_ParametersOutOfRange:
                         Standard_Failure::Raise("Parameters out of range");
                         break;
-#if OCC_VERSION_HEX < 0x060500
-                    case BRepBuilderAPI_SurfaceNotC2:
-                        Standard_Failure::Raise("Surface not C2");
-                        break;
-#endif
                     default:
                         Standard_Failure::Raise("Unknown failure");
                         break;
@@ -847,11 +838,6 @@ PyObject* TopoShapeFacePy::cutHoles(PyObject *args)
                     case BRepBuilderAPI_ParametersOutOfRange:
                         Standard_Failure::Raise("Parameters out of range");
                         break;
-#if OCC_VERSION_HEX < 0x060500
-                    case BRepBuilderAPI_SurfaceNotC2:
-                        Standard_Failure::Raise("Surface not C2");
-                        break;
-#endif
                     default:
                         Standard_Failure::Raise("Unknown failure");
                         break;
diff --git a/src/Mod/Part/App/TopoShapePyImp.cpp b/src/Mod/Part/App/TopoShapePyImp.cpp
index 91d9bcde6f..c3af7be9f6 100644
--- a/src/Mod/Part/App/TopoShapePyImp.cpp
+++ b/src/Mod/Part/App/TopoShapePyImp.cpp
@@ -38,9 +38,7 @@
 # include <BRepProj_Projection.hxx>
 # include <BRepTools.hxx>
 # include <BRepExtrema_DistShapeShape.hxx>
-#if OCC_VERSION_HEX >= 0x060801
 # include <BRepExtrema_ShapeProximity.hxx>
-#endif
 # include <BRepExtrema_SupportType.hxx>
 # include <BRepBndLib.hxx>
 # include <BRep_Tool.hxx>
@@ -182,14 +180,9 @@ PyObject* TopoShapePy::copy(PyObject *args)
     }
 
     if (!shape.IsNull()) {
-#if OCC_VERSION_HEX >= 0x070000
         BRepBuilderAPI_Copy c(shape,
                               PyObject_IsTrue(copyGeom) ? Standard_True : Standard_False,
                               PyObject_IsTrue(copyMesh) ? Standard_True : Standard_False);
-#else
-        BRepBuilderAPI_Copy c(shape,
-                              PyObject_IsTrue(copyGeom) ? Standard_True : Standard_False);
-#endif
         static_cast<TopoShapePy*>(cpy)->getTopoShapePtr()->setShape(c.Shape());
     }
     return cpy;
@@ -2488,10 +2481,8 @@ PyObject* _getSupportIndex(const char* suppStr, TopoShape* ts, TopoDS_Shape supp
 
 PyObject* TopoShapePy::proximity(PyObject *args)
 {
-#if OCC_VERSION_HEX >= 0x060801
-#if OCC_VERSION_HEX >= 0x060901
     typedef BRepExtrema_MapOfIntegerPackedMapOfInteger BRepExtrema_OverlappedSubShapes;
-#endif
+
     PyObject* ps2;
     Standard_Real tol = Precision::Confusion();
     if (!PyArg_ParseTuple(args, "O!|d",&(TopoShapePy::Type), &ps2, &tol))
@@ -2577,11 +2568,7 @@ PyObject* TopoShapePy::proximity(PyObject *args)
     tuple.setItem(0, overlappssindex1);
     tuple.setItem(1, overlappssindex2);
     return Py::new_reference_to(tuple); //face indexes
-#else
-    (void)args;
-    PyErr_SetString(PyExc_NotImplementedError, "proximity requires OCCT >= 6.8.1");
-    return 0;
-#endif
+
 }
 
 PyObject* TopoShapePy::distToShape(PyObject *args)
diff --git a/src/Mod/Part/App/TopoShapeShellPyImp.cpp b/src/Mod/Part/App/TopoShapeShellPyImp.cpp
index 1229a6f375..a5182b33f8 100644
--- a/src/Mod/Part/App/TopoShapeShellPyImp.cpp
+++ b/src/Mod/Part/App/TopoShapeShellPyImp.cpp
@@ -167,11 +167,8 @@ PyObject*  TopoShapeShellPy::getFreeEdges(PyObject *args)
         return nullptr;
     ShapeAnalysis_Shell as;
     as.LoadShells(getTopoShapePtr()->getShape());
-#if OCC_VERSION_HEX < 0x060500
-    as.CheckOrientedShells(getTopoShapePtr()->getShape(), Standard_True);
-#else
     as.CheckOrientedShells(getTopoShapePtr()->getShape(), Standard_True, Standard_True);
-#endif
+
     TopoDS_Compound comp = as.FreeEdges();
     return new TopoShapeCompoundPy(new TopoShape(comp));
 }
@@ -182,11 +179,8 @@ PyObject*  TopoShapeShellPy::getBadEdges(PyObject *args)
         return nullptr;
     ShapeAnalysis_Shell as;
     as.LoadShells(getTopoShapePtr()->getShape());
-#if OCC_VERSION_HEX < 0x060500
     as.CheckOrientedShells(getTopoShapePtr()->getShape(), Standard_True);
-#else
-    as.CheckOrientedShells(getTopoShapePtr()->getShape(), Standard_True, Standard_True);
-#endif
+
     TopoDS_Compound comp = as.BadEdges();
     return new TopoShapeCompoundPy(new TopoShape(comp));
 }
diff --git a/src/Mod/Part/App/TopoShapeSolidPyImp.cpp b/src/Mod/Part/App/TopoShapeSolidPyImp.cpp
index 0df6437b10..ec6b512a03 100644
--- a/src/Mod/Part/App/TopoShapeSolidPyImp.cpp
+++ b/src/Mod/Part/App/TopoShapeSolidPyImp.cpp
@@ -28,9 +28,7 @@
 # include <BRepGProp.hxx>
 # include <BRepTools.hxx>
 # include <BRepOffset_MakeOffset.hxx>
-#if OCC_VERSION_HEX >= 0x060600
 # include <BRepClass3d.hxx>
-#endif
 # include <GProp_GProps.hxx>
 # include <GProp_PrincipalProps.hxx>
 # include <BRepBuilderAPI_MakeSolid.hxx>
@@ -219,11 +217,7 @@ Py::Object TopoShapeSolidPy::getOuterShell(void) const
     TopoDS_Shell shell;
     const TopoDS_Shape& shape = getTopoShapePtr()->getShape();
     if (!shape.IsNull() && shape.ShapeType() == TopAbs_SOLID)
-#if OCC_VERSION_HEX >= 0x060600
         shell = BRepClass3d::OuterShell(TopoDS::Solid(shape));
-#else
-        shell = BRepTools::OuterShell(TopoDS::Solid(shape));
-#endif
     return Py::Object(new TopoShapeShellPy(new TopoShape(shell)),true);
 }
 
diff --git a/src/Mod/Part/App/encodeFilename.h b/src/Mod/Part/App/encodeFilename.h
index 4fadafa3e9..6f86e4241c 100644
--- a/src/Mod/Part/App/encodeFilename.h
+++ b/src/Mod/Part/App/encodeFilename.h
@@ -24,23 +24,11 @@
 #ifndef PART_ENCODEFILENAME_H
 #define PART_ENCODEFILENAME_H
 
-#if (OCC_VERSION_HEX < 0x060800 && defined(_WIN32))
-#include <QString>
-#endif
-
 namespace Part
 {
 inline std::string encodeFilename(std::string fn)
 {
-#if (OCC_VERSION_HEX < 0x060800 && defined(_WIN32))
-    // Workaround to support latin1 characters in path until OCCT supports
-    // conversion from UTF8 to wchar_t on windows
-    // http://tracker.dev.opencascade.org/view.php?id=22484
-    QByteArray str8bit = QString::fromUtf8(fn.c_str()).toLocal8Bit();
-    return std::string(str8bit.constData());
-#else
     return fn;
-#endif
 }
 
 } //namespace Part
diff --git a/src/Mod/Part/App/modelRefine.cpp b/src/Mod/Part/App/modelRefine.cpp
index ada41fe931..cdbf9021d8 100644
--- a/src/Mod/Part/App/modelRefine.cpp
+++ b/src/Mod/Part/App/modelRefine.cpp
@@ -1250,16 +1250,6 @@ void Part::BRepBuilderAPI_RefineModel::Build()
             }
         }
         myShape = mkSolid.Solid();
-
-#if OCC_VERSION_HEX <= 0x060700
-        // With occ 6.7 and older it can happen that a solid is flipped.
-        // In this case it must be reversed
-        GProp_GProps props;
-        BRepGProp::VolumeProperties(myShape, props);
-        if (props.Mass() < 0) {
-            myShape.Reverse();
-        }
-#endif
     }
     else if (myShape.ShapeType() == TopAbs_SHELL) {
         const TopoDS_Shell& shell = TopoDS::Shell(myShape);
diff --git a/src/Mod/Part/BOPTools/__init__.py b/src/Mod/Part/BOPTools/__init__.py
index 8a3ac59154..eb83cbccf4 100644
--- a/src/Mod/Part/BOPTools/__init__.py
+++ b/src/Mod/Part/BOPTools/__init__.py
@@ -64,7 +64,7 @@ def addCommands():
 
 def generalFuseIsAvailable():
     """generalFuseIsAvailable(): returns True if FreeCAD's Part.Shape.generalFuse is functional.
-    True if Part.OCC_VERSION >= 6.9.0."""
+    True if Part.OCC_VERSION >= 7.0.0."""
     import Part
     if not hasattr(Part, "OCC_VERSION"):
         return False
@@ -74,4 +74,4 @@ def generalFuseIsAvailable():
         match = re.match(r"([0-9]+)\.([0-9]+)\.([0-9]+)",ver_string)
         major,minor,rev = match.groups()
         major = int(major); minor = int(minor); rev = int(rev)
-        return (major,minor,rev)>=(6,9,0)
+        return (major,minor,rev)>=(7,0,0)
diff --git a/src/Mod/Part/Gui/Command.cpp b/src/Mod/Part/Gui/Command.cpp
index 2a07634c98..d6ee2f9e14 100644
--- a/src/Mod/Part/Gui/Command.cpp
+++ b/src/Mod/Part/Gui/Command.cpp
@@ -784,11 +784,7 @@ void CmdPartCompSplitFeatures::languageChange()
 bool CmdPartCompSplitFeatures::isActive(void)
 {
     if (getActiveGuiDocument())
-#if OCC_VERSION_HEX < 0x060900
-        return false;
-#else
         return true;
-#endif
     else
         return false;
 }
diff --git a/src/Mod/Part/Gui/CommandSimple.cpp b/src/Mod/Part/Gui/CommandSimple.cpp
index 3393a2ee8f..87263d5a99 100644
--- a/src/Mod/Part/Gui/CommandSimple.cpp
+++ b/src/Mod/Part/Gui/CommandSimple.cpp
@@ -437,18 +437,6 @@ bool CmdPartDefeaturing::isActive(void)
 }
 
 
-// {
-//     if (getActiveGuiDocument())
-// #if OCC_VERSION_HEX < 0x060900
-//         return false;
-// #else
-//         return true;
-// #endif
-//     else
-//         return false;
-// }
-
-
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
 void CreateSimplePartCommands(void)
diff --git a/src/Mod/Part/Gui/PreCompiled.h b/src/Mod/Part/Gui/PreCompiled.h
index 1eabcbbde6..d9a1379c9e 100644
--- a/src/Mod/Part/Gui/PreCompiled.h
+++ b/src/Mod/Part/Gui/PreCompiled.h
@@ -152,10 +152,8 @@
 #include <ShapeFix_Face.hxx>
 #include <ShapeFix_Wireframe.hxx>
 
-#if OCC_VERSION_HEX >= 0x060600
 # include <BOPAlgo_ArgumentAnalyzer.hxx>
 # include <BOPAlgo_ListOfCheckResult.hxx>
-#endif
 
 // Boost
 #include <boost_signals2.hpp>
diff --git a/src/Mod/Part/Gui/TaskCheckGeometry.cpp b/src/Mod/Part/Gui/TaskCheckGeometry.cpp
index 322d0e3fb6..9b0452c0ed 100644
--- a/src/Mod/Part/Gui/TaskCheckGeometry.cpp
+++ b/src/Mod/Part/Gui/TaskCheckGeometry.cpp
@@ -38,11 +38,8 @@
 # include <BRepCheck_ListIteratorOfListOfStatus.hxx>
 # include <BRepBuilderAPI_Copy.hxx>
 # include <BRepTools_ShapeSet.hxx>
-
-# if OCC_VERSION_HEX >= 0x060600
-#  include <BOPAlgo_ArgumentAnalyzer.hxx>
-#  include <BOPAlgo_ListOfCheckResult.hxx>
-# endif
+# include <BOPAlgo_ArgumentAnalyzer.hxx>
+# include <BOPAlgo_ListOfCheckResult.hxx>
 
 # include <TopoDS.hxx>
 # include <TopoDS_Compound.hxx>
@@ -177,7 +174,7 @@ QVector<QString> buildBOPCheckResultVector()
   return results;
 }
 
-#if OCC_VERSION_HEX >= 0x060600
+
 QString getBOPCheckString(const BOPAlgo_CheckStatus &status)
 {
   static QVector<QString> strings = buildBOPCheckResultVector();
@@ -186,7 +183,7 @@ QString getBOPCheckString(const BOPAlgo_CheckStatus &status)
     index = 0;
   return strings.at(index);
 }
-#endif
+
 
 ResultEntry::ResultEntry()
 {
@@ -425,9 +422,7 @@ void TaskCheckGeometryResults::goCheck()
 #if OCC_VERSION_HEX < 0x070500
     Handle(Message_ProgressIndicator) theProgress = new BOPProgressIndicator(tr("Check geometry"), Gui::getMainWindow());
     theProgress->NewScope("BOP check...");
-#if OCC_VERSION_HEX >= 0x060900
     theProgress->Show();
-#endif
 #else
     Handle(Message_ProgressIndicator) theProgress = new BOPProgressIndicator(tr("Check geometry"), Gui::getMainWindow());
     Message_ProgressRange theRange(theProgress->Start());
@@ -647,8 +642,6 @@ int TaskCheckGeometryResults::goBOPSingleCheck(const TopoDS_Shape& shapeIn, Resu
     bool mergeEdgeMode = group->GetBool("MergeEdgeMode", true);
     bool curveOnSurfaceMode = group->GetBool("CurveOnSurfaceMode", true);
 
-    //ArgumentAnalyser was moved at version 6.6. no back port for now.
-#if OCC_VERSION_HEX >= 0x060600
   //Reference use: src/BOPTest/BOPTest_CheckCommands.cxx
 
   //I don't why we need to make a copy, but it doesn't work without it.
@@ -661,35 +654,30 @@ int TaskCheckGeometryResults::goBOPSingleCheck(const TopoDS_Shape& shapeIn, Resu
   //this is left for another time.
   TopoDS_Shape BOPCopy = BRepBuilderAPI_Copy(shapeIn).Shape();
   BOPAlgo_ArgumentAnalyzer BOPCheck;
-#if OCC_VERSION_HEX >= 0x060900
-#if OCC_VERSION_HEX < 0x070500
-  BOPCheck.SetProgressIndicator(theProgress);
-#elif OCC_VERSION_HEX < 0x070600
-  BOPCheck.SetProgressIndicator(theScope);
-#else
-  Q_UNUSED(theScope)
-#endif // 0x070500
-#else
-  Q_UNUSED(theProgress);
-#endif
-//   BOPCheck.StopOnFirstFaulty() = true; //this doesn't run any faster but gives us less results.
+
+  #if OCC_VERSION_HEX < 0x070500
+  	  BOPCheck.SetProgressIndicator(theProgress);
+  #elif OCC_VERSION_HEX < 0x070600
+  	  BOPCheck.SetProgressIndicator(theScope);
+  #else
+  	  Q_UNUSED(theScope)
+  #endif // 0x070500
+
+
   BOPCheck.SetShape1(BOPCopy);
   //all settings are false by default. so only turn on what we want.
   BOPCheck.ArgumentTypeMode() = argumentTypeMode;
   BOPCheck.SelfInterMode() = selfInterMode;
   BOPCheck.SmallEdgeMode() = smallEdgeMode;
   BOPCheck.RebuildFaceMode() = rebuildFaceMode;
-#if OCC_VERSION_HEX >= 0x060700
   BOPCheck.ContinuityMode() = continuityMode;
-#endif
-#if OCC_VERSION_HEX >= 0x060900
+
   BOPCheck.SetParallelMode(!runSingleThreaded); //this doesn't help for speed right now(occt 6.9.1).
   BOPCheck.SetRunParallel(!runSingleThreaded); //performance boost, use all available cores
   BOPCheck.TangentMode() = tangentMode; //these 4 new tests add about 5% processing time.
   BOPCheck.MergeVertexMode() = mergeVertexMode;
   BOPCheck.MergeEdgeMode() = mergeEdgeMode;
   BOPCheck.CurveOnSurfaceMode() = curveOnSurfaceMode;
-#endif
 
 #ifdef FC_DEBUG
   Base::TimeInfo start_time;
@@ -721,14 +709,9 @@ int TaskCheckGeometryResults::goBOPSingleCheck(const TopoDS_Shape& shapeIn, Resu
   for (; BOPResultsIt.More(); BOPResultsIt.Next())
   {
     const BOPAlgo_CheckResult &current = BOPResultsIt.Value();
-
-#if OCC_VERSION_HEX < 0x070000
-    const BOPCol_ListOfShape &faultyShapes1 = current.GetFaultyShapes1();
-    BOPCol_ListIteratorOfListOfShape faultyShapes1It(faultyShapes1);
-#else
     const TopTools_ListOfShape &faultyShapes1 = current.GetFaultyShapes1();
     TopTools_ListIteratorOfListOfShape faultyShapes1It(faultyShapes1);
-#endif
+
     for (;faultyShapes1It.More(); faultyShapes1It.Next())
     {
       const TopoDS_Shape &faultyShape = faultyShapes1It.Value();
@@ -767,9 +750,6 @@ int TaskCheckGeometryResults::goBOPSingleCheck(const TopoDS_Shape& shapeIn, Resu
     }
   }
   return 1;
-#else
-  return 0;
-#endif
 }
 
 
diff --git a/src/Mod/Part/Gui/ViewProviderExt.cpp b/src/Mod/Part/Gui/ViewProviderExt.cpp
index 95651294be..c0431075d8 100644
--- a/src/Mod/Part/Gui/ViewProviderExt.cpp
+++ b/src/Mod/Part/Gui/ViewProviderExt.cpp
@@ -950,12 +950,9 @@ void ViewProviderPartExt::updateVisual()
             deflection = Precision::Confusion();
 
         // create or use the mesh on the data structure
-#if OCC_VERSION_HEX >= 0x060600
         Standard_Real AngDeflectionRads = AngularDeflection.getValue() / 180.0 * M_PI;
         BRepMesh_IncrementalMesh(cShape, deflection, Standard_False, AngDeflectionRads, Standard_True);
-#else
-        BRepMesh_IncrementalMesh(cShape, deflection);
-#endif
+
         // We must reset the location here because the transformation data
         // are set in the placement property
         TopLoc_Location aLoc;
diff --git a/src/Mod/PartDesign/App/FeatureSketchBased.cpp b/src/Mod/PartDesign/App/FeatureSketchBased.cpp
index bf8d9bc1b8..17a4860755 100644
--- a/src/Mod/PartDesign/App/FeatureSketchBased.cpp
+++ b/src/Mod/PartDesign/App/FeatureSketchBased.cpp
@@ -494,11 +494,7 @@ void ProfileBased::getUpToFace(TopoDS_Face& upToFace,
             BRepAdaptor_Surface adapt(upToFace, Standard_False);
             // use the placement of the adapter, not of the upToFace
             loc = TopLoc_Location(adapt.Trsf());
-            BRepBuilderAPI_MakeFace mkFace(adapt.Surface().Surface()
-#if OCC_VERSION_HEX >= 0x060502
-                , Precision::Confusion()
-#endif
-            );
+            BRepBuilderAPI_MakeFace mkFace(adapt.Surface().Surface(), Precision::Confusion());
             if (!mkFace.IsDone())
                 throw Base::ValueError("SketchBased: Up To Face: Failed to create unlimited face");
             upToFace = TopoDS::Face(mkFace.Shape());
@@ -687,12 +683,7 @@ bool ProfileBased::checkLineCrossesFace(const gp_Lin& line, const TopoDS_Face& f
         if (intersector.IsDone()) {
             for (int i = 1; i <= intersector.NbExt(); i++) {
 
-
-#if OCC_VERSION_HEX >= 0x060500
                 if (intersector.SquareDistance(i) < Precision::Confusion()) {
-#else
-                if (intersector.Value(i) < Precision::Confusion()) {
-#endif
                     if (intersector.IsParallel()) {
                         // A line that is coincident with the axis produces three intersections
                         // 1 with the line itself and 2 with the adjacent edges
diff --git a/src/Mod/PartDesign/App/PreCompiled.h b/src/Mod/PartDesign/App/PreCompiled.h
index 4eff1066ee..3eca1395ba 100644
--- a/src/Mod/PartDesign/App/PreCompiled.h
+++ b/src/Mod/PartDesign/App/PreCompiled.h
@@ -98,9 +98,7 @@
 # include <TopoDS.hxx>
 # include <Precision.hxx>
 
-#if OCC_VERSION_HEX >= 0x060800
 # include <OSD_OpenFile.hxx>
-#endif
 
 #endif // _PreComp_
 #endif
diff --git a/src/Mod/PartDesign/Gui/ViewProviderAddSub.cpp b/src/Mod/PartDesign/Gui/ViewProviderAddSub.cpp
index 4b971c4f26..8cfb1ca69c 100644
--- a/src/Mod/PartDesign/Gui/ViewProviderAddSub.cpp
+++ b/src/Mod/PartDesign/Gui/ViewProviderAddSub.cpp
@@ -121,12 +121,8 @@ void ViewProviderAddSub::updateAddSubShapeIndicator() {
         Standard_Real deflection = ((xMax-xMin)+(yMax-yMin)+(zMax-zMin))/300.0 * Deviation.getValue();
 
         // create or use the mesh on the data structure
-#if OCC_VERSION_HEX >= 0x060600
         Standard_Real AngDeflectionRads = AngularDeflection.getValue() / 180.0 * M_PI;
-        BRepMesh_IncrementalMesh(cShape, deflection, Standard_False, AngDeflectionRads, Standard_True);
-#else
-        BRepMesh_IncrementalMesh(cShape, deflection);
-#endif
+
         // We must reset the location here because the transformation data
         // are set in the placement property
         TopLoc_Location aLoc;
diff --git a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
index c6655ac8f9..5816a721ad 100644
--- a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
+++ b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
@@ -214,12 +214,9 @@ void ViewProviderTransformed::showRejectedShape(TopoDS_Shape shape)
 
         // create or use the mesh on the data structure
         // Note: This DOES have an effect on shape
-#if OCC_VERSION_HEX >= 0x060600
         Standard_Real AngDeflectionRads = AngularDeflection.getValue() / 180.0 * M_PI;
         BRepMesh_IncrementalMesh(shape, deflection, Standard_False, AngDeflectionRads, Standard_True);
-#else
-        BRepMesh_IncrementalMesh(shape, deflection);
-#endif
+
         // We must reset the location here because the transformation data
         // are set in the placement property
         TopLoc_Location aLoc;
diff --git a/src/Mod/Path/App/Area.cpp b/src/Mod/Path/App/Area.cpp
index 62b36d7f2e..77e1884160 100644
--- a/src/Mod/Path/App/Area.cpp
+++ b/src/Mod/Path/App/Area.cpp
@@ -860,11 +860,7 @@ struct WireJoiner {
         int rcount = 0;
 
         for (auto& info : edges) {
-#if OCC_VERSION_HEX >= 0x070000
             if (BRep_Tool::IsClosed(info.edge))
-#else
-            if (info.p1.SquareDistance(info.p2) < tol)
-#endif
             {
                 auto wire = BRepBuilderAPI_MakeWire(info.edge).Wire();
                 Area::showShape(wire, "closed");
diff --git a/src/Mod/Sketcher/App/Sketch.cpp b/src/Mod/Sketcher/App/Sketch.cpp
index 490cdf7040..442a0ea127 100644
--- a/src/Mod/Sketcher/App/Sketch.cpp
+++ b/src/Mod/Sketcher/App/Sketch.cpp
@@ -3463,7 +3463,6 @@ bool Sketch::updateGeometry()
                 for(auto it3 = occtknots.begin() ; it3 != occtknots.end(); ++it3)
                     knots.push_back(*it3);
 
-                #if OCC_VERSION_HEX >= 0x060900
                 int index = 0;
                 for(std::vector<int>::const_iterator it5 = mybsp.knotpointGeoids.begin(); it5 != mybsp.knotpointGeoids.end(); ++it5, index++) {
                     if( *it5 != GeoEnum::GeoUndef) {
@@ -3488,8 +3487,6 @@ bool Sketch::updateGeometry()
                         }
                     }
                 }
-                #endif
-
             }
         } catch (Base::Exception &e) {
             Base::Console().Error("Updating geometry: Error build geometry(%d): %s\n",
diff --git a/src/Mod/Sketcher/App/SketchObject.cpp b/src/Mod/Sketcher/App/SketchObject.cpp
index 81e6c4bb41..c75d96978f 100644
--- a/src/Mod/Sketcher/App/SketchObject.cpp
+++ b/src/Mod/Sketcher/App/SketchObject.cpp
@@ -5204,12 +5204,10 @@ int SketchObject::exposeInternalGeometry(int GeoId)
                 else {
                     controlpointgeoids[0] = currentgeoid+incrgeo+1;
                 }
-
                 incrgeo++;
             }
         }
 
-        #if OCC_VERSION_HEX >= 0x060900
         index=0;
 
         for(it=knotgeoids.begin(), itb=knotpoints.begin(); it!=knotgeoids.end() && itb!=knotpoints.end(); ++it, ++itb, index++) {
@@ -5239,21 +5237,8 @@ int SketchObject::exposeInternalGeometry(int GeoId)
                 incrgeo++;
             }
         }
-        #endif
 
         Q_UNUSED(isfirstweightconstrained);
-        // constraint the first weight to allow for seamless weight modification and proper visualization
-        /*if(!isfirstweightconstrained) {
-
-            Sketcher::Constraint *newConstr = new Sketcher::Constraint();
-            newConstr->Type = Sketcher::Radius;
-            newConstr->First = controlpointgeoids[0];
-            newConstr->FirstPos = Sketcher::PointPos::none;
-            newConstr->setValue( round(distance_p0_p1/6)); // 1/6 is just an estimation for acceptable general visualization
-
-            icon.push_back(newConstr);
-
-        }*/
 
         this->addGeometry(igeo,true);
         this->addConstraints(icon);
@@ -5750,10 +5735,6 @@ bool SketchObject::modifyBSplineKnotMultiplicity(int GeoId, int knotIndex, int m
 {
     Base::StateLocker lock(managedoperation, true); // no need to check input data validity as this is an sketchobject managed operation.
 
-    #if OCC_VERSION_HEX < 0x060900
-        THROWMT(Base::NotImplementedError, QT_TRANSLATE_NOOP("Exceptions", "This version of OCE/OCC does not support knot operation. You need 6.9.0 or higher."))
-    #endif
-
     if (GeoId < 0 || GeoId > getHighestCurveIndex())
         THROWMT(Base::ValueError,QT_TRANSLATE_NOOP("Exceptions", "BSpline Geometry Index (GeoID) is out of bounds."))
 
@@ -5927,10 +5908,6 @@ bool SketchObject::insertBSplineKnot(int GeoId, double param, int multiplicity)
 {
     Base::StateLocker lock(managedoperation, true); // TODO: Check if this is still valid: no need to check input data validity as this is an sketchobject managed operation.
 
-    #if OCC_VERSION_HEX < 0x060900
-        THROWMT(Base::NotImplementedError, QT_TRANSLATE_NOOP("Exceptions", "This version of OCE/OCC does not support knot operation. You need 6.9.0 or higher."))
-    #endif
-
     // handling unacceptable cases
     if (GeoId < 0 || GeoId > getHighestCurveIndex())
         THROWMT(Base::ValueError,QT_TRANSLATE_NOOP("Exceptions", "BSpline Geometry Index (GeoID) is out of bounds."));
@@ -6634,11 +6611,7 @@ void SketchObject::rebuildExternalGeometry(void)
     gp_Trsf mov;
     mov.SetValues(invMat[0][0],invMat[0][1],invMat[0][2],invMat[0][3],
                   invMat[1][0],invMat[1][1],invMat[1][2],invMat[1][3],
-                  invMat[2][0],invMat[2][1],invMat[2][2],invMat[2][3]
-#if OCC_VERSION_HEX < 0x060800
-                  , 0.00001, 0.00001
-#endif
-                  ); //precision was removed in OCCT CR0025194
+                  invMat[2][0],invMat[2][1],invMat[2][2],invMat[2][3]);
 
     gp_Ax3 sketchAx3(gp_Pnt(Pos.x,Pos.y,Pos.z),
                      gp_Dir(dN.x,dN.y,dN.z),
@@ -7727,32 +7700,6 @@ double SketchObject::calculateAngleViaPoint(int GeoId1, int GeoId2, double px, d
     }
     else
         throw Base::ValueError("Null geometry in calculateAngleViaPoint");
-
-/*
-    // OCC-based calculation. It is faster, but it was removed due to problems
-    // with reversed geometry (clockwise arcs). More info in "Sketch: how to
-    // handle reversed external arcs?" forum thread
-    // http://forum.freecadweb.org/viewtopic.php?f=10&t=9130&sid=1b994fa1236db5ac2371eeb9a53de23f
-
-    const Part::GeomCurve &g1 = *(dynamic_cast<const Part::GeomCurve*>(this->getGeometry(GeoId1)));
-    const Part::GeomCurve &g2 = *(dynamic_cast<const Part::GeomCurve*>(this->getGeometry(GeoId2)));
-    Base::Vector3d p(px, py, 0.0);
-
-    double u1 = 0.0;
-    double u2 = 0.0;
-    if (! g1.closestParameterToBasicCurve(p, u1) ) throw Base::ValueError("SketchObject::calculateAngleViaPoint: closestParameter(curve1) failed!");
-    if (! g2.closestParameterToBasicCurve(p, u2) ) throw Base::ValueError("SketchObject::calculateAngleViaPoint: closestParameter(curve2) failed!");
-
-    gp_Dir tan1, tan2;
-    if (! g1.tangent(u1,tan1) ) throw Base::ValueError("SketchObject::calculateAngleViaPoint: tangent1 failed!");
-    if (! g2.tangent(u2,tan2) ) throw Base::ValueError("SketchObject::calculateAngleViaPoint: tangent2 failed!");
-
-    assert(abs(tan1.Z())<0.0001);
-    assert(abs(tan2.Z())<0.0001);
-
-    double ang = atan2(-tan2.X()*tan1.Y()+tan2.Y()*tan1.X(), tan2.X()*tan1.X() + tan2.Y()*tan1.Y());
-    return ang;
-*/
 }
 
 void SketchObject::constraintsRenamed(const std::map<App::ObjectIdentifier, App::ObjectIdentifier> &renamed)
diff --git a/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp b/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp
index 2912d77225..78193fefb9 100644
--- a/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp
+++ b/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp
@@ -653,15 +653,6 @@ void CmdSketcherIncreaseKnotMultiplicity::activated(int iMsg)
 {
     Q_UNUSED(iMsg);
 
-#if OCC_VERSION_HEX < 0x060900
-    QMessageBox::warning(Gui::getMainWindow(),
-                         QObject::tr("Wrong OCE/OCC version"),
-                         QObject::tr("This version of OCE/OCC "
-                                     "does not support knot operation. "
-                                     "You need 6.9.0 or higher"));
-    return;
-#endif
-
     // get the selection
     std::vector<Gui::SelectionObject> selection;
     selection = getSelection().getSelectionEx(nullptr, Sketcher::SketchObject::getClassTypeId());
@@ -800,15 +791,6 @@ void CmdSketcherDecreaseKnotMultiplicity::activated(int iMsg)
 {
     Q_UNUSED(iMsg);
 
-#if OCC_VERSION_HEX < 0x060900
-    QMessageBox::warning(Gui::getMainWindow(),
-                         QObject::tr("Wrong OCE/OCC version"),
-                         QObject::tr("This version of OCE/OCC "
-                                     "does not support knot operation. "
-                                     "You need 6.9.0 or higher"));
-    return;
-#endif
-
     // get the selection
     std::vector<Gui::SelectionObject> selection;
     selection = getSelection().getSelectionEx(nullptr, Sketcher::SketchObject::getClassTypeId());
@@ -1175,15 +1157,6 @@ void CmdSketcherInsertKnot::activated(int iMsg)
 {
     Q_UNUSED(iMsg);
 
-#if OCC_VERSION_HEX < 0x060900
-    QMessageBox::warning(Gui::getMainWindow(),
-                         QObject::tr("Wrong OCE/OCC version"),
-                         QObject::tr("This version of OCE/OCC "
-                                     "does not support knot operation. "
-                                     "You need 6.9.0 or higher"));
-    return;
-#endif
-
     // get the selection
     std::vector<Gui::SelectionObject> selection;
     selection = getSelection().getSelectionEx(nullptr, Sketcher::SketchObject::getClassTypeId());
diff --git a/src/Mod/Surface/App/FeatureExtend.cpp b/src/Mod/Surface/App/FeatureExtend.cpp
index 67cf6c9a92..da53f3415f 100644
--- a/src/Mod/Surface/App/FeatureExtend.cpp
+++ b/src/Mod/Surface/App/FeatureExtend.cpp
@@ -143,11 +143,7 @@ App::DocumentObjectExecReturn *Extend::execute(void)
     approx.Init(approxPoints, ParType, DegMin, DegMax, Continuity, Tol3d);
 
     Handle(Geom_BSplineSurface) surface(approx.Surface());
-    BRepBuilderAPI_MakeFace mkFace(surface
-#if OCC_VERSION_HEX >= 0x060502
-      , Precision::Confusion()
-#endif
-    );
+    BRepBuilderAPI_MakeFace mkFace(surface, Precision::Confusion());
 
     Shape.setValue(mkFace.Face());
 
diff --git a/src/Mod/Surface/App/FeatureSections.cpp b/src/Mod/Surface/App/FeatureSections.cpp
index 9583f8b316..7aeccce826 100644
--- a/src/Mod/Surface/App/FeatureSections.cpp
+++ b/src/Mod/Surface/App/FeatureSections.cpp
@@ -92,11 +92,7 @@ App::DocumentObjectExecReturn *Sections::execute(void)
     if (aSurf.IsNull())
         return new App::DocumentObjectExecReturn("Failed to create surface from sections.");
 
-    BRepBuilderAPI_MakeFace mkFace(aSurf
-#if OCC_VERSION_HEX >= 0x060502
-      , Precision::Confusion()
-#endif
-    );
+    BRepBuilderAPI_MakeFace mkFace(aSurf, Precision::Confusion() );
 
     Shape.setValue(mkFace.Face());
     return StdReturn;