diff --git a/include/tins/internals.h b/include/tins/internals.h
index e408f35..5bf8211 100644
--- a/include/tins/internals.h
+++ b/include/tins/internals.h
@@ -216,24 +216,26 @@ template <class T, class P, class=void>
 struct accepts_type : std::false_type { };
 
 template <class T, class P>
-struct accepts_type<T, P, enable_if_t<
-  std::is_same<  decltype(  std::declval<T>()(std::declval<P>())  ), bool>::value
->> : std::true_type { };
+struct accepts_type<T, P, 
+    typename std::enable_if<
+        std::is_same< decltype(  std::declval<T>()(std::declval<P>())  ), bool>::value
+    >::type 
+> : std::true_type { };
 
 // use enable_if to invoke the Packet&& version of the sniff_loop handler if possible - otherwise fail to old behavior
 template <class Functor, class Packet>
 bool invoke_loop_cb(Functor& f, Packet& p, typename std::enable_if<accepts_type<Functor, Packet>::value, bool>::type* = 0) {
-  return f(std::move(p));
+    return f(std::move(p));
 }
 
 template <class Functor, class Packet>
 bool invoke_loop_cb(Functor& f, Packet& p, typename std::enable_if<!accepts_type<Functor, Packet>::value && accepts_type<Functor, Packet&>::value, bool>::type* = 0) {
-  return f(p);
+    return f(p);
 }
 
 template <class Functor, class Packet>
 bool invoke_loop_cb(Functor& f, Packet& p, typename std::enable_if<!accepts_type<Functor, Packet>::value && !accepts_type<Functor, Packet&>::value, bool>::type* = 0) {
-  return f(*p.pdu());
+    return f(*p.pdu());
 }
 #endif