diff --git a/toonz/sources/include/ext/plasticskeleton.h b/toonz/sources/include/ext/plasticskeleton.h
index fc3e64f..64b4902 100644
--- a/toonz/sources/include/ext/plasticskeleton.h
+++ b/toonz/sources/include/ext/plasticskeleton.h
@@ -139,14 +139,10 @@ public:
 	std::vector<PlasticHandle> verticesToHandles() const;
 
 public:
-// RValues-related functions
-#ifndef BOOST_NO_RVALUE_REFERENCES
-
+	// RValues-related functions
 	PlasticSkeleton(PlasticSkeleton &&other);
 	PlasticSkeleton &operator=(PlasticSkeleton &&other);
 
-#endif
-
 private:
 	friend class PlasticSkeletonDeformation; // Skeleton deformations can register to be notified
 
diff --git a/toonz/sources/tnzext/plasticskeleton.cpp b/toonz/sources/tnzext/plasticskeleton.cpp
index 5b909ed..97c075b 100644
--- a/toonz/sources/tnzext/plasticskeleton.cpp
+++ b/toonz/sources/tnzext/plasticskeleton.cpp
@@ -103,12 +103,8 @@ public:
 	Imp(const Imp &other);
 	Imp &operator=(const Imp &other);
 
-#ifndef BOOST_NO_RVALUE_REFERENCES
-
 	Imp(Imp &&other);
 	Imp &operator=(Imp &&other);
-
-#endif
 };
 
 //===============================================================================
@@ -127,9 +123,6 @@ PlasticSkeleton::Imp &PlasticSkeleton::Imp::operator=(const Imp &other)
 }
 
 //-------------------------------------------------------------------------------
-
-#ifndef BOOST_NO_RVALUE_REFERENCES
-
 PlasticSkeleton::Imp::Imp(Imp &&other)
 	: m_numbersPool(std::move(other.m_numbersPool))
 {
@@ -143,8 +136,6 @@ PlasticSkeleton::Imp &PlasticSkeleton::Imp::operator=(Imp &&other)
 	return *this;
 }
 
-#endif
-
 //************************************************************************************
 //    PlasticSkeleton  implementation
 //************************************************************************************
@@ -181,9 +172,6 @@ PlasticSkeleton &PlasticSkeleton::operator=(const PlasticSkeleton &other)
 }
 
 //------------------------------------------------------------------
-
-#ifndef BOOST_NO_RVALUE_REFERENCES
-
 PlasticSkeleton::PlasticSkeleton(PlasticSkeleton &&other)
 	: mesh_type(std::forward<mesh_type>(other)), m_imp(new Imp(std::move(*other.m_imp)))
 {
@@ -201,8 +189,6 @@ PlasticSkeleton &PlasticSkeleton::operator=(PlasticSkeleton &&other)
 	return *this;
 }
 
-#endif
-
 //------------------------------------------------------------------
 
 void PlasticSkeleton::addListener(PlasticSkeletonDeformation *deformation)