diff --git a/go.mod b/go.mod
index 4ccf356..bea54cb 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,4 @@ module github.com/unistack-org/micro-client-http/v3
 
 go 1.16
 
-require github.com/unistack-org/micro/v3 v3.4.8
+require github.com/unistack-org/micro/v3 v3.5.2
diff --git a/go.sum b/go.sum
index c02593b..f8847d3 100644
--- a/go.sum
+++ b/go.sum
@@ -1,12 +1,12 @@
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/ef-ds/deque v1.0.4/go.mod h1:gXDnTC3yqvBcHbq2lcExjtAcVrOnJCbMcZXmuj8Z4tg=
-github.com/google/uuid v1.2.0 h1:qJYtXnJRWmpe7m/3XlyhrsLrEURqHRM2kxzoxXqyUDs=
-github.com/google/uuid v1.2.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/imdario/mergo v0.3.12/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
 github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/silas/dag v0.0.0-20210121180416-41cf55125c34/go.mod h1:7RTUFBdIRC9nZ7/3RyRNH1bdqIShrDejd1YbLwgPS+I=
-github.com/unistack-org/micro/v3 v3.4.8 h1:9+qGlNHgChC3aMuFrtTFUtG55PEAjneSvplg7phwoCI=
-github.com/unistack-org/micro/v3 v3.4.8/go.mod h1:LXmPfbJnJNvL0kQs8HfnkV3Wya2Wb+C7keVq++RCZnk=
+github.com/unistack-org/micro/v3 v3.5.2 h1:8b9Mk4FLWRLp8SduBh5Xs6g/3xJ+ZIBOnH82eHuLWnw=
+github.com/unistack-org/micro/v3 v3.5.2/go.mod h1:1ZkwpEqpiHiVhM2hiF9DamtpsF04oFybFhEQ4zEMcro=
 golang.org/x/net v0.0.0-20210510120150-4163338589ed/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
diff --git a/http.go b/http.go
index 653b5fa..cec0d95 100644
--- a/http.go
+++ b/http.go
@@ -126,7 +126,7 @@ func newRequest(ctx context.Context, addr string, req client.Request, ct string,
 	}
 
 	if opts.AuthToken != "" {
-		hreq.Header.Set("Authorization", opts.AuthToken)
+		hreq.Header.Set(metadata.HeaderAuthorization, opts.AuthToken)
 	}
 
 	if md, ok := metadata.FromOutgoingContext(ctx); ok {
@@ -137,14 +137,14 @@ func newRequest(ctx context.Context, addr string, req client.Request, ct string,
 
 	// set timeout in nanoseconds
 	if opts.StreamTimeout > time.Duration(0) {
-		hreq.Header.Set("Timeout", fmt.Sprintf("%d", opts.StreamTimeout))
+		hreq.Header.Set(metadata.HeaderTimeout, fmt.Sprintf("%d", opts.StreamTimeout))
 	}
 	if opts.RequestTimeout > time.Duration(0) {
-		hreq.Header.Set("Timeout", fmt.Sprintf("%d", opts.RequestTimeout))
+		hreq.Header.Set(metadata.HeaderTimeout, fmt.Sprintf("%d", opts.RequestTimeout))
 	}
 
 	// set the content type for the request
-	hreq.Header.Set("Content-Type", ct)
+	hreq.Header.Set(metadata.HeaderContentType, ct)
 
 	return hreq, nil
 }
@@ -539,8 +539,8 @@ func (h *httpClient) Publish(ctx context.Context, p client.Message, opts ...clie
 	if !ok {
 		md = metadata.New(2)
 	}
-	md["Content-Type"] = p.ContentType()
-	md["Micro-Topic"] = p.Topic()
+	md[metadata.HeaderContentType] = p.ContentType()
+	md[metadata.HeaderTopic] = p.Topic()
 
 	cf, err := h.newCodec(p.ContentType())
 	if err != nil {