diff --git a/agents/httpagent.go b/agents/httpagent.go
index b6e3f2429..8922df5f1 100644
--- a/agents/httpagent.go
+++ b/agents/httpagent.go
@@ -45,11 +45,11 @@ func NewHTTPAgent(connMgr *engine.ConnManager, sessionConns []string,
 
 // HTTPAgent is a handler for HTTP requests
 type HTTPAgent struct {
-	connMgr *engine.ConnManager
-	filterS *engine.FilterS
-	dfltTenant,
-	reqPayload,
-	rplyPayload string
+	connMgr       *engine.ConnManager
+	filterS       *engine.FilterS
+	dfltTenant    string
+	reqPayload    string
+	rplyPayload   string
 	reqProcessors []*config.RequestProcessor
 	sessionConns  []string
 }
diff --git a/agents/libhttpagent_test.go b/agents/libhttpagent_test.go
index eb14657db..dad06fd57 100644
--- a/agents/libhttpagent_test.go
+++ b/agents/libhttpagent_test.go
@@ -24,7 +24,6 @@ import (
 	"net/http"
 	"strings"
 	"testing"
-	//"github.com/cgrates/cgrates/utils"
 )
 
 func TestHttpUrlDPFieldAsInterface(t *testing.T) {
diff --git a/agents/sipagent.go b/agents/sipagent.go
index dc404077a..555b841f8 100644
--- a/agents/sipagent.go
+++ b/agents/sipagent.go
@@ -21,6 +21,7 @@ package agents
 import (
 	"fmt"
 	"net"
+	"regexp"
 	"sync"
 	"time"
 
@@ -43,6 +44,10 @@ const (
 	method          = "Method"
 )
 
+var (
+	sipTagRgx = regexp.MustCompile(`tag=([^ ,;>]*)`)
+)
+
 // NewSIPAgent will construct a SIPAgent
 func NewSIPAgent(connMgr *engine.ConnManager, cfg *config.CGRConfig,
 	filterS *engine.FilterS) (sa *SIPAgent, err error) {
@@ -228,10 +233,12 @@ func (sa *SIPAgent) answerMessage(messageStr, addr string, write func(ans []byte
 				utils.SIPAgent, err.Error(), messageStr))
 		return // do we need to return error in case we can't parse the message?
 	}
-	key := utils.ConcatenatedKey(sipMessage[fromHeader], sipMessage[callIDHeader])
+	tags := sipTagRgx.FindStringSubmatch(sipMessage[fromHeader])
+	// in case we get a wrong sip message ( without tag in the From header) the next line should panic
+	key := utils.ConcatenatedKey(sipMessage[callIDHeader], tags[1])
 	method := sipMessage.MethodFrom(requestHeader)
 	if ackMethod == method {
-		if sa.cfg.SIPAgentCfg().ACKInterval == 0 { // ignore ACK
+		if sa.cfg.SIPAgentCfg().RetransmissionTimer == 0 { // ignore ACK
 			return
 		}
 		sa.ackLocks.Lock()
@@ -255,7 +262,7 @@ func (sa *SIPAgent) answerMessage(messageStr, addr string, write func(ans []byte
 	}
 	// because we expext to send codes from 300-699 we wait for the ACK every time
 	if method != inviteMethod || // only invitest need ACK
-		sa.cfg.SIPAgentCfg().ACKInterval == 0 {
+		sa.cfg.SIPAgentCfg().RetransmissionTimer == 0 {
 		return // disabled ACK
 	}
 	stopChan := make(chan struct{})
@@ -265,7 +272,7 @@ func (sa *SIPAgent) answerMessage(messageStr, addr string, write func(ans []byte
 	go func(stopChan chan struct{}, a []byte) {
 		for {
 			select {
-			case <-time.After(sa.cfg.SIPAgentCfg().ACKInterval):
+			case <-time.After(sa.cfg.SIPAgentCfg().RetransmissionTimer):
 				if err = write(ans); err != nil {
 					utils.Logger.Warning(
 						fmt.Sprintf("<%s> error: %s sending message: %s",
@@ -285,7 +292,7 @@ func (sa *SIPAgent) answerMessage(messageStr, addr string, write func(ans []byte
 
 func (sa *SIPAgent) handleMessage(sipMessage sipingo.Message, remoteHost string) (sipAnswer sipingo.Message) {
 	if sipMessage[userAgentHeader] != "" {
-		sipMessage[userAgentHeader] = utils.CGRateS
+		sipMessage[userAgentHeader] = fmt.Sprintf("%s@%s", utils.CGRateS, utils.VERSION)
 	}
 	sipMessageIface := make(map[string]interface{})
 	for k, v := range sipMessage {
diff --git a/config/config_defaults.go b/config/config_defaults.go
index 7819643a8..0e07c646d 100755
--- a/config/config_defaults.go
+++ b/config/config_defaults.go
@@ -941,7 +941,7 @@ const CGRATES_CFG_JSON = `
 	"listen_net": "udp",				// network to listen on <udp|tcp|tcp-tls>
 	"sessions_conns": ["*internal"],
 	"timezone": "",						// timezone of the events if not specified  <UTC|Local|$IANA_TZ_DB>
-	"ack_interval": "1s",				// the duration to wait to receive an ACK before resending the reply
+	"retransmission_timer": "1s",				// the duration to wait to receive an ACK before resending the reply
 	"templates":{						// default message templates
 		"*err": [
 				{"tag": "Request", "path": "*rep.Request", "type": "*constant",
diff --git a/config/libconfig_json.go b/config/libconfig_json.go
index 92906c256..40c636bfd 100755
--- a/config/libconfig_json.go
+++ b/config/libconfig_json.go
@@ -622,12 +622,12 @@ type RateSJsonCfg struct {
 
 // SIPAgentJsonCfg
 type SIPAgentJsonCfg struct {
-	Enabled            *bool
-	Listen             *string
-	Listen_net         *string
-	Sessions_conns     *[]string
-	Timezone           *string
-	Ack_interval       *string
-	Templates          map[string][]*FcTemplateJsonCfg
-	Request_processors *[]*ReqProcessorJsnCfg
+	Enabled              *bool
+	Listen               *string
+	Listen_net           *string
+	Sessions_conns       *[]string
+	Timezone             *string
+	Retransmission_timer *string
+	Templates            map[string][]*FcTemplateJsonCfg
+	Request_processors   *[]*ReqProcessorJsnCfg
 }
diff --git a/config/sipagentcfg.go b/config/sipagentcfg.go
index e7a2e1538..de433e882 100644
--- a/config/sipagentcfg.go
+++ b/config/sipagentcfg.go
@@ -26,14 +26,14 @@ import (
 )
 
 type SIPAgentCfg struct {
-	Enabled           bool
-	Listen            string
-	ListenNet         string // udp or tcp
-	SessionSConns     []string
-	Timezone          string
-	ACKInterval       time.Duration // timeout replies if not reaching back
-	Templates         map[string][]*FCTemplate
-	RequestProcessors []*RequestProcessor
+	Enabled             bool
+	Listen              string
+	ListenNet           string // udp or tcp
+	SessionSConns       []string
+	Timezone            string
+	RetransmissionTimer time.Duration // timeout replies if not reaching back
+	Templates           map[string][]*FCTemplate
+	RequestProcessors   []*RequestProcessor
 }
 
 func (da *SIPAgentCfg) loadFromJsonCfg(jsnCfg *SIPAgentJsonCfg, sep string) (err error) {
@@ -63,8 +63,8 @@ func (da *SIPAgentCfg) loadFromJsonCfg(jsnCfg *SIPAgentJsonCfg, sep string) (err
 			}
 		}
 	}
-	if jsnCfg.Ack_interval != nil {
-		if da.ACKInterval, err = utils.ParseDurationWithNanosecs(*jsnCfg.Ack_interval); err != nil {
+	if jsnCfg.Retransmission_timer != nil {
+		if da.RetransmissionTimer, err = utils.ParseDurationWithNanosecs(*jsnCfg.Retransmission_timer); err != nil {
 			return err
 		}
 	}
diff --git a/migrator/migrator.go b/migrator/migrator.go
index 0875dcced..bf0992556 100755
--- a/migrator/migrator.go
+++ b/migrator/migrator.go
@@ -54,7 +54,7 @@ type Migrator struct {
 	dryRun     bool
 	sameDataDB bool
 	sameStorDB bool
-	sameOutDB  bool
+	sameOutDB  bool // needed in case we set version and we use same DataDB as StorDB to store the versions without overwriting them
 	stats      map[string]int
 }