diff --git a/EGkSurfTriMesh.h b/EGkSurfTriMesh.h
index ff07308..97adc87 100644
--- a/EGkSurfTriMesh.h
+++ b/EGkSurfTriMesh.h
@@ -53,7 +53,7 @@ class __declspec( novtable) ISurfTriMesh : public ISurf
       virtual bool CreateByScrewing( const PolyLine& PL, const Point3d& ptAx, const Vector3d& vtAx,
                                      double dAngRot, double dStepRot, double dMove) = 0 ;
       virtual bool DoCompacting( double dTol = EPS_SMALL) = 0 ;
-      virtual bool DoSewing( const ISurfTriMesh& stmOther, const Frame3d& frOther = GLOB_FRM) = 0 ;
+      virtual bool DoSewing( const ISurfTriMesh& stmOther, const Frame3d& frOther = GLOB_FRM, double dTol = 2 * EPS_SMALL) = 0 ;
       virtual int  GetVertexCount( void) const = 0 ;
       virtual int  GetTriangleCount( void) const = 0 ;
       virtual int  GetTriangleCount( int nTFlag) const = 0 ;
diff --git a/EgtKeyCodes.h b/EgtKeyCodes.h
index 477644e..ba8d31c 100644
--- a/EgtKeyCodes.h
+++ b/EgtKeyCodes.h
@@ -1,7 +1,7 @@
 //----------------------------------------------------------------------------
-//  EgalTech 2015-2020
+//  EgalTech 2015-2021
 //----------------------------------------------------------------------------
-// File : EgtKeyCodes.h       Data : 04.08.20        Versione : 2.2h1
+// File : EgtKeyCodes.h       Data : 31.07.21        Versione : 2.3h1
 // Contenuto : Costanti per codici di protezione librerie di base.
 //
 //
@@ -21,7 +21,7 @@
 
 //----------------------------------------------------------------------------
 const int KEY_BASELIB_PROD = 207 ;
-const int KEY_BASELIB_VER = 2307 ;
+const int KEY_BASELIB_VER = 2308 ;
 const int KEY_BASELIB_LEV = 1 ;
 
 //----------------------------------------------------------------------------