diff --git a/src/msgpack_packer.erl b/src/msgpack_packer.erl
index 861f3ff..053a1c6 100644
--- a/src/msgpack_packer.erl
+++ b/src/msgpack_packer.erl
@@ -66,6 +66,10 @@ pack({string, String}, ?OPTION{spec=new, pack_str=from_tagged_list}=Opt) ->
         {error, _} -> throw({badarg, String});
         Bin when is_binary(Bin) -> Bin
     end;
+
+pack({array, List}, ?OPTION{spec=new, pack_str=from_list}=Opt)  when is_list(List) ->
+    pack_array(List, Opt);
+
 pack(List, ?OPTION{spec=new, pack_str=from_list}=Opt)  when is_list(List) ->
     try
         case lists:all(fun is_integer/1, List) of
@@ -154,8 +158,24 @@ pack_uint(N) when (N band 16#FFFFFFFF) =:= N->
 pack_uint(N) when (N band 16#FFFFFFFFFFFFFFFF) =:= N ->
     << 16#CF:8, N:64/big-unsigned-integer-unit:1 >>;
 %% too big unit
-pack_uint(N) ->
-    throw({badarg, N}).
+% https://github.com/msgpack/msgpack/blob/73b3adb3099ef93326a4c93864d8f29e69b0c545/spec.md#bigint-extension-type
+pack_uint(N) when N > 0 ->
+  Bin=binary:encode_unsigned(N),
+  BS = byte_size(Bin),
+  if BS==1 -> <<16#d4:8, Bin/binary>>;
+     BS==2 -> <<16#d5:8, Bin/binary>>;
+     BS==4 -> <<16#d5:8, Bin/binary>>;
+     BS==8 -> <<16#d5:8, Bin/binary>>;
+     BS==16 -> <<16#d5:8, Bin/binary>>;
+     BS < 256 ->
+       <<16#C7:8, BS:8/big, -2:8/signed, Bin/binary>>;
+     BS <65536 ->
+       <<16#C8:8, BS:16/big, -2:8/signed, Bin/binary>>;
+     BS < 4294967296 ->
+       <<16#C9:8, BS:32/big, -2:8/signed, Bin/binary>>;
+     true ->
+       throw({badarg, N})
+  end.
 
 
 %% @doc float : erlang's float is always IEEE 754 64bit format. Thus it
diff --git a/src/msgpack_unpacker.erl b/src/msgpack_unpacker.erl
index 3484466..9d7817c 100644
--- a/src/msgpack_unpacker.erl
+++ b/src/msgpack_unpacker.erl
@@ -259,6 +259,9 @@ unpack_str(Binary) ->
 maybe_unpack_ext(F, _, _, _, _Rest, _, ?OPTION{spec=old}) ->
     %% trying to unpack new ext formats with old unpacker
     throw({badarg, {new_spec, F}});
+% https://github.com/msgpack/msgpack/blob/73b3adb3099ef93326a4c93864d8f29e69b0c545/spec.md#bigint-extension-type
+maybe_unpack_ext(_, _, -2, Data, Rest, _, _) ->
+    {binary:decode_unsigned(Data, big), Rest};
 maybe_unpack_ext(F, undefined, _, _, _Rest, _, _) ->
     throw({badarg, {bad_ext, F}});
 maybe_unpack_ext(_, Unpack, Type, Data, Rest, Orig, _)
diff --git a/test/msgpack_tests.erl b/test/msgpack_tests.erl
index 7b3c5b5..7114eed 100644
--- a/test/msgpack_tests.erl
+++ b/test/msgpack_tests.erl
@@ -386,6 +386,29 @@ atom_test_() ->
                        <<"atom2">>=><<"binary2">>}}, msgpack:unpack(Bin)),
     ?_assertEqual({ok,Map1}, msgpack:unpack(Bin,[{known_atoms,[atom1,atom2]}])).
 
+list_pack_test_() ->
+    [
+     {"list or string",
+      fun() ->
+              Source=#{
+                string=>"hello",
+                bad_array=>[ 104,101,108,108,111 ],
+                array=>{array,[ 104,101,108,108,111 ]}
+               },
+              Bin=msgpack:pack(Source,[{spec, new}, {pack_str,from_list}]),
+              {ok,Repacked}=msgpack:unpack(Bin,[{spec,
+                                                 new},
+                                                {unpack_str,as_tagged_list}]),
+              ?assertMatch(#{
+                 <<"string">> := {string,"hello"},
+                 <<"bad_array">> := {string, "hello"},
+                 <<"array">> := [ 104,101,108,108,111 ]
+                }, Repacked)
+      end
+     }
+    ].
+
+
 -define(PCNT, 5).
 -define(CNT, 10000).