diff --git a/go.mod b/go.mod
index 49466da..a0dafab 100644
--- a/go.mod
+++ b/go.mod
@@ -11,7 +11,7 @@ require (
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.2.1
 	github.com/stretchr/testify v1.7.0
-	github.com/ugorji/go/codec v1.1.7
+	github.com/ugorji/go/codec v1.2.6
 	github.com/valyala/gorpc v0.0.0-20160519171614-908281bef774
 	golang.org/x/mod v0.4.0
 	golang.org/x/sys v0.0.0-20201207223542-d4d67f95c62d // indirect
diff --git a/go.sum b/go.sum
index 7f455df..03a7c4c 100644
--- a/go.sum
+++ b/go.sum
@@ -94,10 +94,10 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXf
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/ugorji/go v1.1.7 h1:/68gy2h+1mWMrwZFeD1kQialdSzAb432dtpeJ42ovdo=
-github.com/ugorji/go v1.1.7/go.mod h1:kZn38zHttfInRq0xu/PH0az30d+z6vm202qpg1oXVMw=
-github.com/ugorji/go/codec v1.1.7 h1:2SvQaVZ1ouYrrKKwoSk2pzd4A9evlKJb9oTL+OaLUSs=
-github.com/ugorji/go/codec v1.1.7/go.mod h1:Ax+UKWsSmolVDwsd+7N3ZtXu+yMGCf907BLYF3GoBXY=
+github.com/ugorji/go v1.2.6 h1:tGiWC9HENWE2tqYycIqFTNorMmFRVhNwCpDOpWqnk8E=
+github.com/ugorji/go v1.2.6/go.mod h1:anCg0y61KIhDlPZmnH+so+RQbysYVyDko0IMgJv0Nn0=
+github.com/ugorji/go/codec v1.2.6 h1:7kbGefxLoDBuYXOms4yD7223OpNMMPNPZxXk5TvFcyQ=
+github.com/ugorji/go/codec v1.2.6/go.mod h1:V6TCNZ4PHqoHGFZuSG1W8nrCzzdgA2DozYxWFFpvxTw=
 github.com/valyala/gorpc v0.0.0-20160519171614-908281bef774 h1:SUHFQHAaySqF0YHCmmm0EIFooFZpDPpi5KTom7YJ07c=
 github.com/valyala/gorpc v0.0.0-20160519171614-908281bef774/go.mod h1:8uNqM1i7pr0jO7gdvbNCgsSa8Ki2vMh7JCQxO9BlF90=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
diff --git a/transport.go b/transport.go
index eb87121..e77a62d 100644
--- a/transport.go
+++ b/transport.go
@@ -2,6 +2,7 @@ package gotsrpc
 
 import (
 	"net/http"
+	"reflect"
 
 	"github.com/ugorji/go/codec"
 )
@@ -25,6 +26,8 @@ var msgpackClientHandle = &clientHandle{
 
 func init() {
 	mh := new(codec.MsgpackHandle)
+	// use map[string]interface{} instead of map[interface{}]interface{}
+	mh.MapType = reflect.TypeOf(map[string]interface{}(nil))
 	msgpackClientHandle.handle = mh
 	// attempting to set promoted field in literal will cause a compiler error
 	mh.RawToString = true