diff --git a/build.sh b/build.sh
index c994b98..5059486 100755
--- a/build.sh
+++ b/build.sh
@@ -1,5 +1,5 @@
 #/bash/sh
-export VERSION=0.25.3
+export VERSION=0.25.4
 
 sudo apt-get install gcc-mingw-w64-i686
 env GOOS=windows GOARCH=386 CGO_ENABLED=1 CC=i686-w64-mingw32-gcc go build -ldflags "-s -w -extldflags -static -extldflags -static" -buildmode=c-shared -o npc_sdk.dll cmd/npc/sdk.go
@@ -175,5 +175,5 @@ echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin
 export DOCKER_CLI_EXPERIMENTAL=enabled
 docker run --rm --privileged docker/binfmt:66f9012c56a8316f9244ffd7622d7c21c1f6f28d
 docker buildx create --use --name mybuilder
-docker buildx build --tag ffdfgdfg/nps:$VERSION --output type=image,push=true --file Dockerfile.nps --platform=linux/amd64,linux/arm64,linux/386,linux/arm .
-docker buildx build --tag ffdfgdfg/npc:$VERSION --output type=image,push=true --file Dockerfile.npc --platform=linux/amd64,linux/arm64,linux/386,linux/arm .
+docker buildx build --tag ffdfgdfg/nps:$VERSION --tag ffdfgdfg/nps:latest --output type=image,push=true --file Dockerfile.nps --platform=linux/amd64,linux/arm64,linux/386,linux/arm .
+docker buildx build --tag ffdfgdfg/npc:$VERSION --tag ffdfgdfg/npc:latest --output type=image,push=true --file Dockerfile.npc --platform=linux/amd64,linux/arm64,linux/386,linux/arm .
diff --git a/docs/_coverpage.md b/docs/_coverpage.md
index cb361da..68e0cc3 100644
--- a/docs/_coverpage.md
+++ b/docs/_coverpage.md
@@ -1,6 +1,6 @@
 ![logo](logo.svg)
 
-# NPS <small>0.25.2</small>
+# NPS <small>0.25.4</small>
 
 > 一款轻量级、高性能、功能强大的内网穿透代理服务器
 
diff --git a/docs/nps_use.md b/docs/nps_use.md
index 4058869..2681e8b 100644
--- a/docs/nps_use.md
+++ b/docs/nps_use.md
@@ -40,4 +40,6 @@
  nps-update.exe update
 ```
 
-更新完成后，执行执行`sudo nps start`或者`nps.exe start`重新运行即可完成升级
\ No newline at end of file
+更新完成后，执行执行`sudo nps start`或者`nps.exe start`重新运行即可完成升级
+
+如果无法更新成功，可以直接自行下载releases压缩包然后覆盖原有的nps二进制文件和web目录
diff --git a/docs/use.md b/docs/use.md
index 00547b2..5f775ab 100644
--- a/docs/use.md
+++ b/docs/use.md
@@ -36,6 +36,8 @@ npc-update.exe update
 
 更新完成后，执行执行`sudo npc start`或者`npc.exe start`重新运行即可完成升级
 
+如果无法更新成功，可以直接自行下载releases压缩包然后覆盖原有的npc二进制文件
+
 ## 配置文件模式
 此模式使用nps的公钥或者客户端私钥验证，各种配置在客户端完成，同时服务端web也可以进行管理
 ```
diff --git a/gui/npc/AndroidManifest.xml b/gui/npc/AndroidManifest.xml
index 463634d..901a508 100755
--- a/gui/npc/AndroidManifest.xml
+++ b/gui/npc/AndroidManifest.xml
@@ -2,7 +2,7 @@
 <manifest
         xmlns:android="http://schemas.android.com/apk/res/android"
         android:versionCode="1"
-        android:versionName="0.25.3"
+        android:versionName="0.25.4"
         package="org.nps.client"
         platformBuildVersionCode="15"
         platformBuildVersionName="4.0.4-1406430">
diff --git a/lib/common/netpackager.go b/lib/common/netpackager.go
index cf4b988..c6956f5 100644
--- a/lib/common/netpackager.go
+++ b/lib/common/netpackager.go
@@ -246,6 +246,15 @@ func (Self *MuxPackager) UnPack(reader io.Reader) (n uint16, err error) {
 	return
 }
 
+func (Self *MuxPackager) reset() {
+	Self.Id = 0
+	Self.Flag = 0
+	Self.Length = 0
+	Self.Content = nil
+	Self.ReadLength = 0
+	Self.Window = 0
+}
+
 const (
 	ipV4       = 1
 	domainName = 3
diff --git a/lib/common/pool.go b/lib/common/pool.go
index 3ed19dc..31931f9 100644
--- a/lib/common/pool.go
+++ b/lib/common/pool.go
@@ -93,18 +93,20 @@ type windowBufferPool struct {
 func (Self *windowBufferPool) New() {
 	Self.pool = sync.Pool{
 		New: func() interface{} {
-			return make([]byte, PoolSizeWindow, PoolSizeWindow)
+			return make([]byte, PoolSizeWindow)
 		},
 	}
 }
 
 func (Self *windowBufferPool) Get() (buf []byte) {
 	buf = Self.pool.Get().([]byte)
-	return buf[:PoolSizeWindow]
+	buf = buf[:PoolSizeWindow]
+	return buf
 }
 
 func (Self *windowBufferPool) Put(x []byte) {
-	Self.pool.Put(x[:PoolSizeWindow]) // make buf to full
+	x = x[:0] // clean buf
+	Self.pool.Put(x)
 }
 
 type bufferPool struct {
@@ -146,6 +148,7 @@ func (Self *muxPackagerPool) Get() *MuxPackager {
 }
 
 func (Self *muxPackagerPool) Put(pack *MuxPackager) {
+	pack.reset()
 	Self.pool.Put(pack)
 }
 
diff --git a/lib/install/install.go b/lib/install/install.go
index 66bb28b..6156e3f 100644
--- a/lib/install/install.go
+++ b/lib/install/install.go
@@ -91,11 +91,13 @@ func copyStaticFile(srcPath, bin string) string {
 			if _, err := copyFile(filepath.Join(srcPath, bin), "/usr/local/bin/"+bin); err != nil {
 				log.Fatalln(err)
 			} else {
-				copyFile(filepath.Join(srcPath, "nps"), "/usr/local/bin/"+bin+"-update")
+				copyFile(filepath.Join(srcPath, bin), "/usr/local/bin/"+bin+"-update")
+				chMod("/usr/local/bin/"+bin+"-update", 0755)
 				binPath = "/usr/local/bin/" + bin
 			}
 		} else {
-			copyFile(filepath.Join(srcPath, "nps"), "/usr/bin/"+bin+"-update")
+			copyFile(filepath.Join(srcPath, bin), "/usr/bin/"+bin+"-update")
+			chMod("/usr/bin/"+bin+"-update", 0755)
 			binPath = "/usr/bin/" + bin
 		}
 	} else {
diff --git a/lib/mux/conn.go b/lib/mux/conn.go
index 28ec1de..52fb642 100644
--- a/lib/mux/conn.go
+++ b/lib/mux/conn.go
@@ -2,6 +2,7 @@ package mux
 
 import (
 	"errors"
+	"github.com/astaxie/beego/logs"
 	"io"
 	"math"
 	"net"
@@ -215,10 +216,10 @@ func (Self *ReceiveWindow) calcSize() {
 		if n < common.MAXIMUM_SEGMENT_SIZE*10 {
 			n = common.MAXIMUM_SEGMENT_SIZE * 10
 		}
-		bufLen := Self.bufQueue.Len()
-		if n < bufLen {
-			n = bufLen
-		}
+		//bufLen := Self.bufQueue.Len()
+		//if n < bufLen {
+		//	n = bufLen
+		//}
 		if n < Self.maxSize/2 {
 			n = Self.maxSize / 2
 		}
@@ -227,6 +228,7 @@ func (Self *ReceiveWindow) calcSize() {
 			n = 2 * Self.maxSize
 		}
 		if n > (common.MAXIMUM_WINDOW_SIZE / uint32(conns)) {
+			logs.Warn("window too large", n)
 			n = common.MAXIMUM_WINDOW_SIZE / uint32(conns)
 		}
 		// set the maximum size
@@ -444,7 +446,20 @@ func (Self *SendWindow) allow() {
 }
 
 func (Self *SendWindow) sent(sentSize uint32) {
-	atomic.AddUint64(&Self.remainingWait, ^(uint64(sentSize)<<dequeueBits - 1))
+	var remaining, wait uint32
+	for {
+		ptrs := atomic.LoadUint64(&Self.remainingWait)
+		remaining, wait = Self.unpack(ptrs)
+		if remaining >= sentSize {
+			atomic.AddUint64(&Self.remainingWait, ^(uint64(sentSize)<<dequeueBits - 1))
+			break
+		} else {
+			if atomic.CompareAndSwapUint64(&Self.remainingWait, ptrs, Self.pack(0, wait)) {
+				// just keep the wait status, it will be wait in the next loop
+				break
+			}
+		}
+	}
 }
 
 func (Self *SendWindow) WriteTo() (p []byte, sendSize uint32, part bool, err error) {
diff --git a/lib/mux/mux.go b/lib/mux/mux.go
index ae9f335..ab02323 100644
--- a/lib/mux/mux.go
+++ b/lib/mux/mux.go
@@ -5,7 +5,9 @@ import (
 	"io"
 	"math"
 	"net"
+	"os"
 	"sync/atomic"
+	"syscall"
 	"time"
 
 	"github.com/astaxie/beego/logs"
@@ -35,13 +37,17 @@ func NewMux(c net.Conn, connType string) *Mux {
 	//c.(*net.TCPConn).SetReadBuffer(0)
 	//c.(*net.TCPConn).SetWriteBuffer(0)
 	_ = c.SetDeadline(time.Time{})
+	fd, err := getConnFd(c)
+	if err != nil {
+		logs.Warn(err)
+	}
 	m := &Mux{
 		conn:      c,
 		connMap:   NewConnMap(),
 		id:        0,
 		closeChan: make(chan struct{}, 1),
 		newConnCh: make(chan *conn),
-		bw:        new(bandwidth),
+		bw:        NewBandwidth(fd),
 		IsClose:   false,
 		connType:  connType,
 		pingCh:    make(chan []byte),
@@ -58,6 +64,26 @@ func NewMux(c net.Conn, connType string) *Mux {
 	return m
 }
 
+func getConnFd(c net.Conn) (fd *os.File, err error) {
+	switch c.(type) {
+	case *net.TCPConn:
+		fd, err = c.(*net.TCPConn).File()
+		if err != nil {
+			return
+		}
+		return
+	case *net.UDPConn:
+		fd, err = c.(*net.UDPConn).File()
+		if err != nil {
+			return
+		}
+		return
+	default:
+		err = errors.New("mux:unknown conn type, only tcp or kcp")
+		return
+	}
+}
+
 func (s *Mux) NewConn() (*conn, error) {
 	if s.IsClose {
 		return nil, errors.New("the mux has closed")
@@ -392,13 +418,19 @@ type bandwidth struct {
 	readStart     time.Time
 	lastReadStart time.Time
 	bufLength     uint32
+	fd            *os.File
+	calcThreshold uint32
+}
+
+func NewBandwidth(fd *os.File) *bandwidth {
+	return &bandwidth{fd: fd}
 }
 
 func (Self *bandwidth) StartRead() {
 	if Self.readStart.IsZero() {
 		Self.readStart = time.Now()
 	}
-	if Self.bufLength >= common.MAXIMUM_SEGMENT_SIZE*300 {
+	if Self.bufLength >= Self.calcThreshold {
 		Self.lastReadStart, Self.readStart = Self.readStart, time.Now()
 		Self.calcBandWidth()
 	}
@@ -410,7 +442,21 @@ func (Self *bandwidth) SetCopySize(n uint16) {
 
 func (Self *bandwidth) calcBandWidth() {
 	t := Self.readStart.Sub(Self.lastReadStart)
-	atomic.StoreUint64(&Self.readBandwidth, math.Float64bits(float64(Self.bufLength)/t.Seconds()))
+	bufferSize, err := syscall.GetsockoptInt(int(Self.fd.Fd()), syscall.SOL_SOCKET, syscall.SO_RCVBUF)
+	//logs.Warn(bufferSize)
+	if err != nil {
+		logs.Warn(err)
+		Self.bufLength = 0
+		return
+	}
+	if Self.bufLength >= uint32(bufferSize) {
+		atomic.StoreUint64(&Self.readBandwidth, math.Float64bits(float64(Self.bufLength)/t.Seconds()))
+		// calculate the hole socket buffer, the time meaning to fill the buffer
+		//logs.Warn(Self.Get())
+	} else {
+		Self.calcThreshold = uint32(bufferSize)
+	}
+	// socket buffer size is bigger than bufLength, so we don't calculate it
 	Self.bufLength = 0
 }
 
diff --git a/lib/version/version.go b/lib/version/version.go
index 78dbbef..c2f1489 100644
--- a/lib/version/version.go
+++ b/lib/version/version.go
@@ -1,6 +1,6 @@
 package version
 
-const VERSION = "0.25.3"
+const VERSION = "0.25.4"
 
 // Compulsory minimum version, Minimum downward compatibility to this version
 func GetVersion() string {