diff --git a/.travis.yml b/.travis.yml
index a4792d9..0f74d91 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,5 @@
 language: erlang
 otp_release:
-       - 17.0-rc1
        - R16B03-1
        - R16B03
        - R16B02
diff --git a/rebar.config b/rebar.config
index 057e498..07a123c 100644
--- a/rebar.config
+++ b/rebar.config
@@ -9,7 +9,8 @@
 
 %% Compiler Options ============================================================
 {erl_opts,
- [debug_info,
+ [{platform_define, "^[0-9]+", namespaced_types},
+  debug_info,
   warnings_as_errors]}.
 
 %% EUnit =======================================================================
diff --git a/src/ec_dict.erl b/src/ec_dict.erl
index 49f3d96..0c0b998 100644
--- a/src/ec_dict.erl
+++ b/src/ec_dict.erl
@@ -34,7 +34,11 @@
 %%%===================================================================
 %% This should be opaque, but that kills dialyzer so for now we export it
 %% however you should not rely on the internal representation here
+-ifdef(namespaced_types).
+-type dictionary(_K, _V) :: dict:dict().
+-else.
 -type dictionary(_K, _V) :: dict().
+-endif.
 
 %%%===================================================================
 %%% API
diff --git a/src/ec_plists.erl b/src/ec_plists.erl
index 7512fdc..4726c18 100644
--- a/src/ec_plists.erl
+++ b/src/ec_plists.erl
@@ -480,9 +480,17 @@ usort(Fun, List, Malt) ->
     runmany(Fun2, {recursive, Fuse}, List, Malt).
 
 %% @doc Like below, assumes default MapMalt of 1.
+-ifdef(namespaced_types).
+-spec mapreduce/2 :: (MapFunc, list()) -> dict:dict() when
+      MapFunc ::  fun((term()) -> DeepListOfKeyValuePairs),
+      DeepListOfKeyValuePairs :: [DeepListOfKeyValuePairs] | {Key::term(), Value::term()}.
+-else.
 -spec mapreduce/2 :: (MapFunc, list()) -> dict() when
       MapFunc ::  fun((term()) -> DeepListOfKeyValuePairs),
       DeepListOfKeyValuePairs :: [DeepListOfKeyValuePairs] | {Key::term(), Value::term()}.
+-endif.
+
+
 mapreduce(MapFunc, List) ->
     mapreduce(MapFunc, List, 1).
 
@@ -510,10 +518,17 @@ mapreduce(MapFunc, List, MapMalt) ->
 %%
 %% mapreduce requires OTP R11B, or it may leave monitoring messages in the
 %% message queue.
+-ifdef(namespaced_types).
+-spec mapreduce/5 :: (MapFunc, list(), InitState::term(), ReduceFunc, malt()) -> dict:dict() when
+      MapFunc :: fun((term()) -> DeepListOfKeyValuePairs),
+      DeepListOfKeyValuePairs :: [DeepListOfKeyValuePairs] | {Key::term(), Value::term()},
+      ReduceFunc :: fun((OldState::term(), Key::term(), Value::term()) -> NewState::term()).
+-else.
 -spec mapreduce/5 :: (MapFunc, list(), InitState::term(), ReduceFunc, malt()) -> dict() when
       MapFunc :: fun((term()) -> DeepListOfKeyValuePairs),
       DeepListOfKeyValuePairs :: [DeepListOfKeyValuePairs] | {Key::term(), Value::term()},
       ReduceFunc :: fun((OldState::term(), Key::term(), Value::term()) -> NewState::term()).
+-endif.
 mapreduce(MapFunc, List, InitState, ReduceFunc, MapMalt) ->
     Parent = self(),
     {Reducer, ReducerRef} =