diff --git a/ndn-cxx/detail/nonstd/optional-lite.hpp b/ndn-cxx/detail/nonstd/optional-lite.hpp
index b4fde93..2c9f122 100644
--- a/ndn-cxx/detail/nonstd/optional-lite.hpp
+++ b/ndn-cxx/detail/nonstd/optional-lite.hpp
@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2014-2018 Martin Moene
+// Copyright (c) 2014-2021 Martin Moene
 //
 // https://github.com/martinmoene/optional-lite
 //
@@ -12,7 +12,7 @@
 #define NONSTD_OPTIONAL_LITE_HPP
 
 #define optional_lite_MAJOR  3
-#define optional_lite_MINOR  4
+#define optional_lite_MINOR  5
 #define optional_lite_PATCH  0
 
 #define optional_lite_VERSION  optional_STRINGIFY(optional_lite_MAJOR) "." optional_STRINGIFY(optional_lite_MINOR) "." optional_STRINGIFY(optional_lite_PATCH)
@@ -47,7 +47,7 @@
 // Control presence of exception handling (try and auto discover):
 
 #ifndef optional_CONFIG_NO_EXCEPTIONS
-# if _MSC_VER
+# if defined(_MSC_VER)
 # include <cstddef>     // for _HAS_EXCEPTIONS
 # endif
 # if defined(__cpp_exceptions) || defined(__EXCEPTIONS) || (_HAS_EXCEPTIONS)
@@ -1106,7 +1106,7 @@
     >
     optional_constexpr explicit optional( nonstd_lite_in_place_t(T), Args&&... args )
     : has_value_( true )
-    , contained( T( std::forward<Args>(args)...) )
+    , contained( in_place, std::forward<Args>(args)... )
     {}
 
     // 7 (C++11) - in-place construct,  initializer-list
diff --git a/ndn-cxx/detail/nonstd/scope-lite.hpp b/ndn-cxx/detail/nonstd/scope-lite.hpp
index 03699d3..aa8ce4c 100644
--- a/ndn-cxx/detail/nonstd/scope-lite.hpp
+++ b/ndn-cxx/detail/nonstd/scope-lite.hpp
@@ -13,7 +13,7 @@
 #define NONSTD_SCOPE_LITE_HPP
 
 #define scope_lite_MAJOR  0
-#define scope_lite_MINOR  1
+#define scope_lite_MINOR  2
 #define scope_lite_PATCH  0
 
 #define scope_lite_VERSION  scope_STRINGIFY(scope_lite_MAJOR) "." scope_STRINGIFY(scope_lite_MINOR) "." scope_STRINGIFY(scope_lite_PATCH)
@@ -27,6 +27,20 @@
 #define scope_SCOPE_NONSTD   1
 #define scope_SCOPE_STD      2
 
+// tweak header support:
+
+#ifdef __has_include
+# if __has_include(<nonstd/scope.tweak.hpp>)
+#  include <nonstd/scope.tweak.hpp>
+# endif
+#define scope_HAVE_TWEAK_HEADER  1
+#else
+#define scope_HAVE_TWEAK_HEADER  0
+//# pragma message("scope.hpp: Note: Tweak header not supported.")
+#endif
+
+// scope selection and configuration:
+
 #if !defined( scope_CONFIG_SELECT_SCOPE )
 # define scope_CONFIG_SELECT_SCOPE  ( scope_HAVE_STD_SCOPE ? scope_SCOPE_STD : scope_SCOPE_NONSTD )
 #endif
@@ -203,11 +217,14 @@
 #define scope_HAVE_IS_COPY_CONSTRUCTIBLE  scope_CPP11_110
 #define scope_HAVE_IS_MOVE_CONSTRUCTIBLE  scope_CPP11_110
 #define scope_HAVE_IS_NOTHROW_CONSTRUCTIBLE scope_CPP11_110
+#define scope_HAVE_IS_NOTHROW_COPY_CONSTRUCTIBLE scope_CPP11_110
 #define scope_HAVE_IS_NOTHROW_MOVE_CONSTRUCTIBLE scope_CPP11_110
 #define scope_HAVE_IS_COPY_ASSIGNABLE     scope_CPP11_110
 #define scope_HAVE_IS_NOTHROW_ASSIGNABLE  scope_CPP11_110
 #define scope_HAVE_IS_NOTHROW_MOVE_ASSIGNABLE  scope_CPP11_110
 
+#define scope_HAVE_REFERENCE_WRAPPER      scope_CPP11_110
+
 #define scope_HAVE_REMOVE_CV              scope_CPP11_90
 #define scope_HAVE_REMOVE_REFERENCE       scope_CPP11_90
 
@@ -457,7 +474,6 @@
     template< class T > struct remove_reference{ typedef T type; };
 #endif
 
-
 #if scope_HAVE( REFERENCE_WRAPPER )
     using std::reference_wrapper;
 #else
@@ -1225,14 +1241,11 @@
     }
 };
 
-template< typename Policy >
+template< typename Policy, typename Action >
 class scope_guard : public Policy
 {
 public:
-    typedef void (*Action)();
-
-    template< typename Fn >
-    scope_guard( Fn action )
+    scope_guard( Action action )
         : Policy()
         , action_( action )
     {}
@@ -1255,25 +1268,25 @@
     Action action_;
 };
 
-class scope_exit : public scope_guard< on_exit_policy >
+template< typename Fn = void(*)() >
+class scope_exit : public scope_guard< on_exit_policy, Fn >
 {
 public:
-    template< typename Fn >
-    scope_exit( Fn action ) : scope_guard( action ) {}
+    scope_exit( Fn action ) : scope_guard<on_exit_policy, Fn>( action ) {}
 };
 
-class scope_fail : public scope_guard< on_fail_policy >
+template< typename Fn = void(*)() >
+class scope_fail : public scope_guard< on_fail_policy, Fn >
 {
 public:
-    template< typename Fn >
-    scope_fail( Fn action ) : scope_guard( action ) {}
+    scope_fail( Fn action ) : scope_guard<on_fail_policy, Fn>( action ) {}
 };
 
-class scope_success : public scope_guard< on_success_policy >
+template< typename Fn = void(*)() >
+class scope_success : public scope_guard< on_success_policy, Fn >
 {
 public:
-    template< typename Fn >
-    scope_success( Fn action ) : scope_guard( action ) {}
+    scope_success( Fn action ) : scope_guard<on_success_policy, Fn>( action ) {}
 };
 
 // unique_resource (C++98):
@@ -1380,21 +1393,21 @@
 };
 
 template< class EF >
-scope_exit make_scope_exit( EF action )
+scope_exit<EF> make_scope_exit( EF action )
 {
-    return scope_exit( action );
+    return scope_exit<EF>( action );
 }
 
 template< class EF >
-scope_fail make_scope_fail( EF action )
+scope_fail<EF> make_scope_fail( EF action )
 {
-    return scope_fail( action );
+    return scope_fail<EF>( action );
 }
 
 template< class EF >
-scope_success make_scope_success( EF action )
+scope_success<EF> make_scope_success( EF action )
 {
-    return scope_success( action );
+    return scope_success<EF>( action );
 }
 
 template< class R, class D, class S >