diff --git a/go.mod b/go.mod
index 293a054..af3435d 100644
--- a/go.mod
+++ b/go.mod
@@ -1,4 +1,4 @@
-module go.unistack.org/micro-server-grpc/v3
+module go.unistack.org/micro-server-grpc/v4
 
 go 1.22.0
 
diff --git a/grpc.go b/grpc.go
index 4926078..b8294f6 100644
--- a/grpc.go
+++ b/grpc.go
@@ -44,13 +44,6 @@ const (
 	DefaultContentType = "application/grpc"
 )
 
-/*
-type ServerReflection struct {
-	srv *grpc.Server
-	s   *serverReflectionServer
-}
-*/
-
 type streamWrapper struct {
 	ctx context.Context
 	grpc.ServerStream
@@ -99,22 +92,6 @@ func newServer(opts ...server.Option) *Server {
 	return g
 }
 
-/*
-type grpcRouter struct {
- h func(context.Context, server.Request, interface{}) error
- m func(context.Context, server.Message) error
-}
-
-func (r grpcRouter) ProcessMessage(ctx context.Context, msg server.Message) error {
- return r.m(ctx, msg)
-}
-
-func (r grpcRouter) ServeRequest(ctx context.Context, req server.Request, rsp server.Response) error {
- return r.h(ctx, req, rsp)
-}
-
-*/
-
 func (g *Server) configure(opts ...server.Option) error {
 	g.Lock()
 	defer g.Unlock()
@@ -210,8 +187,9 @@ func (g *Server) handler(srv interface{}, stream grpc.ServerStream) error {
 		return status.Errorf(codes.Internal, "method does not exist in context")
 	}
 
+	var gmd map[string][]string
 	// get grpc metadata
-	gmd, ok := gmetadata.FromIncomingContext(ctx)
+	gmd, ok = gmetadata.FromIncomingContext(ctx)
 	if !ok {
 		gmd = gmetadata.MD{}
 	}
@@ -244,12 +222,10 @@ func (g *Server) handler(srv interface{}, stream grpc.ServerStream) error {
 		}()
 	}
 
-	md := metadata.New(len(gmd))
-	for k, v := range gmd {
-		md[k] = v
-	}
-	md.Set("Path", fullMethod)
-	md.Set("Micro-Server", "grpc")
+	md := metadata.Copy(gmd)
+
+	md.Set("path", fullMethod)
+	md.Set("micro-server", "grpc")
 	md.Set(metadata.HeaderEndpoint, methodName)
 	md.Set(metadata.HeaderService, serviceName)
 
@@ -259,8 +235,8 @@ func (g *Server) handler(srv interface{}, stream grpc.ServerStream) error {
 		md.Del("timeout")
 		td = v[0]
 	}
-	if v, ok := md.Get("Grpc-Timeout"); ok && len(v) > 0 {
-		md.Del("Grpc-Timeout")
+	if v, ok := md.Get("grpc-timeout"); ok && len(v) > 0 {
+		md.Del("grpc-timeout")
 		td = v[0][:len(v)-1]
 		switch v[0][len(v)-1:] {
 		case "S":
@@ -283,9 +259,6 @@ func (g *Server) handler(srv interface{}, stream grpc.ServerStream) error {
 
 	if ctype, ok := md.Get("content-type"); ok && len(ctype) > 0 {
 		ct = ctype[0]
-	} else if ctype, ok := md.Get("x-content-type"); ok && len(ctype) > 0 {
-		ct = ctype[0]
-		md.Del("x-content-type")
 	}
 
 	// create new context
@@ -318,7 +291,7 @@ func (g *Server) handler(srv interface{}, stream grpc.ServerStream) error {
 
 	// get peer from context
 	if p, ok := peer.FromContext(ctx); ok {
-		md.Set("Remote", p.Addr.String())
+		md.Set("remote", p.Addr.String())
 		ctx = peer.NewContext(ctx, p)
 	}