diff --git a/debug.hpp b/debug.hpp
index 6fc074d..6ada1fc 100644
--- a/debug.hpp
+++ b/debug.hpp
@@ -33,11 +33,7 @@
 #define LUTOK_DEBUG_HPP
 
 #include <string>
-#if defined(_LIBCPP_VERSION) || __cplusplus >= 201103L
 #include <memory>
-#else
-#include <tr1/memory>
-#endif
 
 namespace lutok {
 
@@ -59,11 +55,7 @@ class debug {
     struct impl;
 
     /// Pointer to the shared internal implementation.
-#if defined(_LIBCPP_VERSION) || __cplusplus >= 201103L
     std::shared_ptr< impl > _pimpl;
-#else
-    std::tr1::shared_ptr< impl > _pimpl;
-#endif
 
 public:
     debug(void);
diff --git a/state.hpp b/state.hpp
index 377aa06..3b088f1 100644
--- a/state.hpp
+++ b/state.hpp
@@ -32,13 +32,8 @@
 #if !defined(LUTOK_STATE_HPP)
 #define LUTOK_STATE_HPP
 
-#include <string>
-
-#if defined(_LIBCPP_VERSION) || __cplusplus >= 201103L
 #include <memory>
-#else
-#include <tr1/memory>
-#endif
+#include <string>
 
 namespace lutok {
 
@@ -77,11 +72,7 @@ class state {
     struct impl;
 
     /// Pointer to the shared internal implementation.
-#if defined(_LIBCPP_VERSION) || __cplusplus >= 201103L
     std::shared_ptr< impl > _pimpl;
-#else
-    std::tr1::shared_ptr< impl > _pimpl;
-#endif
 
     void* new_userdata_voidp(const size_t);
     void* to_userdata_voidp(const int);