diff --git a/go.mod b/go.mod
index 9ff57f21..4e29fb66 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@ require (
 	github.com/brocaar/lorawan v0.0.0-20230210103351-84b137ed1908
 	github.com/chirpstack/chirpstack/api/go/v4 v4.3.1
 	github.com/eclipse/paho.mqtt.golang v1.4.2
-	github.com/go-zeromq/zmq4 v0.7.0
+	github.com/go-zeromq/zmq4 v0.15.0
 	github.com/golang-jwt/jwt/v4 v4.5.0
 	github.com/goreleaser/goreleaser v0.106.0
 	github.com/goreleaser/nfpm v0.11.0
@@ -71,7 +71,6 @@ require (
 	golang.org/x/sys v0.7.0 // indirect
 	golang.org/x/text v0.9.0 // indirect
 	golang.org/x/tools v0.6.0 // indirect
-	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
diff --git a/go.sum b/go.sum
index 5c379a82..e732b619 100644
--- a/go.sum
+++ b/go.sum
@@ -498,8 +498,8 @@ github.com/go-redis/redis/v8 v8.8.3/go.mod h1:ik7vb7+gm8Izylxu6kf6wG26/t2VljgCfS
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-zeromq/goczmq/v4 v4.2.2 h1:HAJN+i+3NW55ijMJJhk7oWxHKXgAuSBkoFfvr8bYj4U=
 github.com/go-zeromq/goczmq/v4 v4.2.2/go.mod h1:Sm/lxrfxP/Oxqs0tnHD6WAhwkWrx+S+1MRrKzcxoaYE=
-github.com/go-zeromq/zmq4 v0.7.0 h1:tmmTVfWB0HYo+8Ra0DK2MJIDl1lsvuU/J9559hpLU7s=
-github.com/go-zeromq/zmq4 v0.7.0/go.mod h1:fo1rWyfV/bsg7tq/F9LF1H0e2Cf3ovQFoge1G21AnWU=
+github.com/go-zeromq/zmq4 v0.15.0 h1:SLqukpmLTx0JsLaOaCCjwy5eBdfJ+ouJX/677HoFbJM=
+github.com/go-zeromq/zmq4 v0.15.0/go.mod h1:sD47DcXifeUFsVTB2ps8ijqTpEuTAlYgfuLoiWEXdCE=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
@@ -1222,7 +1222,6 @@ golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20220411194840-2f41105eb62f/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20220517211312-f3a8303e98df/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
 golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
-golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 h1:H2TDz8ibqkAF6YGhCdN3jS9O0/s90v0rJh3X/OLHEUk=
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
 google.golang.org/api v0.4.0/go.mod h1:8k5glujaEP+g9n7WNsDg8QP6cUVNI86fCNMcbazEtwE=
 google.golang.org/api v0.7.0/go.mod h1:WtwebWUNSVBH/HAw79HIFXZNqEvBhG+Ra+ax0hx3E3M=
diff --git a/internal/backend/concentratord/concentratord.go b/internal/backend/concentratord/concentratord.go
index b6bff1b3..bb19147f 100644
--- a/internal/backend/concentratord/concentratord.go
+++ b/internal/backend/concentratord/concentratord.go
@@ -263,7 +263,8 @@ func (b *Backend) commandRequest(command string, v proto.Message) ([]byte, error
 		return nil, errors.Wrap(err, "receive command request reply error")
 	}
 
-	return reply.Bytes(), nil
+	// Return last frame.
+	return reply.Frames[len(reply.Frames)-1], nil
 }
 
 func (b *Backend) eventLoop() {
diff --git a/internal/backend/concentratord/concentratord_test.go b/internal/backend/concentratord/concentratord_test.go
index 014d37de..ae730e5d 100644
--- a/internal/backend/concentratord/concentratord_test.go
+++ b/internal/backend/concentratord/concentratord_test.go
@@ -70,7 +70,6 @@ func (ts *BackendTestSuite) SetupTest() {
 	wg.Wait()
 
 	assert.Equal(events.Subscribe{
-
 		Subscribe: true,
 		GatewayID: lorawan.EUI64{1, 2, 3, 4, 5, 6, 7, 8},
 	}, <-subscribeEventChan)