diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4a31255..79e283f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # ChangeLog for pymycobot
 
+## v3.3.1 (2023-12-4)
+
+- release v3.3.1
+- fix bug
+
 ## v3.3.0 (2023-11-9)
 
 - release v3.3.0
diff --git a/pymycobot/__init__.py b/pymycobot/__init__.py
index 4c88da6..1c560a2 100644
--- a/pymycobot/__init__.py
+++ b/pymycobot/__init__.py
@@ -52,7 +52,7 @@
     from pymycobot.mybuddyemoticon import MyBuddyEmoticon
     __all__.append("MyBuddyEmoticon")
 
-__version__ = "3.3.0b0"
+__version__ = "3.3.1"
 __author__ = "Elephantrobotics"
 __email__ = "weiquan.xu@elephantrobotics.com"
 __git_url__ = "https://github.com/elephantrobotics/pymycobot"
diff --git a/pymycobot/mecharmsocket.py b/pymycobot/mecharmsocket.py
index 8fcf4df..80e77b2 100644
--- a/pymycobot/mecharmsocket.py
+++ b/pymycobot/mecharmsocket.py
@@ -110,7 +110,12 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_FRESH_MODE,
                 ProtocolCode.GET_GRIPPER_MODE,
                 ProtocolCode.GET_ERROR_INFO,
-                ProtocolCode.GET_GPIO_IN
+                ProtocolCode.GET_GPIO_IN,
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]:
diff --git a/pymycobot/myarm.py b/pymycobot/myarm.py
index aa75224..d74071f 100644
--- a/pymycobot/myarm.py
+++ b/pymycobot/myarm.py
@@ -109,8 +109,13 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_REFERENCE_FRAME,
                 ProtocolCode.GET_FRESH_MODE,
                 ProtocolCode.GET_GRIPPER_MODE,
+                ProtocolCode.GET_ERROR_INFO,
                 ProtocolCode.SET_SSID_PWD,
-                ProtocolCode.GetHTSGripperTorque
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]:
diff --git a/pymycobot/myarmsocket.py b/pymycobot/myarmsocket.py
index e870347..4fa5f99 100644
--- a/pymycobot/myarmsocket.py
+++ b/pymycobot/myarmsocket.py
@@ -110,7 +110,13 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_FRESH_MODE,
                 ProtocolCode.GET_GRIPPER_MODE,
                 ProtocolCode.GET_ERROR_INFO,
-                ProtocolCode.GET_GPIO_IN
+                ProtocolCode.GET_GPIO_IN,
+                ProtocolCode.SET_SSID_PWD,
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]:
diff --git a/pymycobot/mybuddy.py b/pymycobot/mybuddy.py
index ba92f3d..e099e3d 100644
--- a/pymycobot/mybuddy.py
+++ b/pymycobot/mybuddy.py
@@ -158,9 +158,12 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_END_TYPE,
                 ProtocolCode.GET_MOVEMENT_TYPE,
                 ProtocolCode.GET_REFERENCE_FRAME,
-                ProtocolCode.GET_JOINT_MIN_ANGLE,
-                ProtocolCode.GET_JOINT_MAX_ANGLE,
                 ProtocolCode.GET_FRESH_MODE,
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
                 # ProtocolCode.GET_SERVO_CURRENTS
             ]:
                 return self._process_single(res)
@@ -192,6 +195,8 @@ def _mesg(self, genre, *args, **kwargs):
                     return r
                 else:
                     return res
+            elif genre in [ProtocolCode.GET_JOINT_MAX_ANGLE, ProtocolCode.GET_JOINT_MIN_ANGLE]:
+                return self._int2coord(res[0])
             elif genre in [ProtocolCode.GET_SERVO_VOLTAGES, ProtocolCode.COLLISION]:
                 return [self._int2coord(angle) for angle in res]
             else:
diff --git a/pymycobot/mybuddysocket.py b/pymycobot/mybuddysocket.py
index 8407c92..8e6cb95 100644
--- a/pymycobot/mybuddysocket.py
+++ b/pymycobot/mybuddysocket.py
@@ -118,7 +118,12 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_MOVEMENT_TYPE,
                 ProtocolCode.GET_REFERENCE_FRAME,
                 ProtocolCode.GET_JOINT_MIN_ANGLE,
-                ProtocolCode.GET_JOINT_MAX_ANGLE
+                ProtocolCode.GET_JOINT_MAX_ANGLE,
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]:
diff --git a/pymycobot/mycobot.py b/pymycobot/mycobot.py
index e755581..1880f5e 100755
--- a/pymycobot/mycobot.py
+++ b/pymycobot/mycobot.py
@@ -125,7 +125,11 @@ def _res(self, real_command, has_reply, genre):
                 ProtocolCode.GET_ERROR_INFO,
                 ProtocolCode.GET_COMMUNICATE_MODE,
                 ProtocolCode.SET_COMMUNICATE_MODE,
-                ProtocolCode.GetHTSGripperTorque
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]:
diff --git a/pymycobot/mycobotsocket.py b/pymycobot/mycobotsocket.py
index ab2b3d6..6ab36b0 100644
--- a/pymycobot/mycobotsocket.py
+++ b/pymycobot/mycobotsocket.py
@@ -113,7 +113,12 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_ERROR_INFO,
                 ProtocolCode.GET_GPIO_IN,
                 ProtocolCode.GET_COMMUNICATE_MODE,
-                ProtocolCode.SET_COMMUNICATE_MODE
+                ProtocolCode.SET_COMMUNICATE_MODE,
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]:
diff --git a/pymycobot/mypalletizer.py b/pymycobot/mypalletizer.py
index 01a7453..fdf1638 100644
--- a/pymycobot/mypalletizer.py
+++ b/pymycobot/mypalletizer.py
@@ -145,7 +145,12 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_BASIC_INPUT,
                 ProtocolCode.GET_TOF_DISTANCE,
                 ProtocolCode.GET_COMMUNICATE_MODE,
-                ProtocolCode.SET_COMMUNICATE_MODE
+                ProtocolCode.SET_COMMUNICATE_MODE,
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]:
diff --git a/pymycobot/mypalletizersocket.py b/pymycobot/mypalletizersocket.py
index c9cade1..045e2fc 100644
--- a/pymycobot/mypalletizersocket.py
+++ b/pymycobot/mypalletizersocket.py
@@ -106,7 +106,12 @@ def _mesg(self, genre, *args, **kwargs):
                 ProtocolCode.GET_TOF_DISTANCE,
                 ProtocolCode.GET_GPIO_IN,
                 ProtocolCode.GET_COMMUNICATE_MODE,
-                ProtocolCode.SET_COMMUNICATE_MODE
+                ProtocolCode.SET_COMMUNICATE_MODE,
+                ProtocolCode.SetHTSGripperTorque,
+                ProtocolCode.GetHTSGripperTorque,
+                ProtocolCode.GetGripperProtectCurrent,
+                ProtocolCode.InitGripper,
+                ProtocolCode.SET_FOUR_PIECES_ZERO
             ]:
                 return self._process_single(res)
             elif genre in [ProtocolCode.GET_ANGLES]: