diff --git a/README.md b/README.md
index 042c005..a3f00ef 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,11 @@
 
 This integration has been tested with Solarfocus eco<sup>manager-touch</sup> version `21.040`.
 
-Added biomass boiler pellet statistics (available since version 23.010)
+Added biomass boiler pellet statistics (available since version 23.010). To have them available, choose the respective API version when instantiating the client:
+
+```python
+solarfocus = SolarfocusAPI(ip="[Your-IP]", system=Systems.Vampair, api_version=ApiVersions.V_23_010)
+```
 
 ### Systems
 
diff --git a/example.py b/example.py
index 4b4be58..afe8b2f 100644
--- a/example.py
+++ b/example.py
@@ -1,8 +1,9 @@
-from pysolarfocus import SolarfocusAPI,Systems
+from pysolarfocus import SolarfocusAPI,Systems,ApiVersions
 
 # Create the Solarfocus API client
-# TODO: Adapt IP-Address
-solarfocus = SolarfocusAPI(ip="IP-Address", system=Systems.Therminator)
+# TODO: Choose either Vampair or Therminator and adapt IP-Address and version
+solarfocus = SolarfocusAPI(ip="IP-Address", system=Systems.Vampair, api_version=ApiVersions.V_21_140)
+
 solarfocus.connect()
 # Fetch the values
 solarfocus.update()
@@ -14,9 +15,10 @@
 print("\n")
 print(solarfocus.buffers[0])
 print("\n")
-print(solarfocus.pelletsboiler)
-print("\n")
-print(solarfocus.heatpump)
+if solarfocus.system is Systems.Therminator:
+    print(solarfocus.pelletsboiler)
+if solarfocus.system is Systems.Vampair:
+    print(solarfocus.heatpump)
 print("\n")
 print(solarfocus.photovoltaic)
 print("\n")
diff --git a/pyproject.toml b/pyproject.toml
index 46c51e7..a09fa5c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pysolarfocus"
-version = "3.4.0"
+version = "3.5.0"
 description = "Unofficial, local Solarfocus client"
 authors = ["Jeroen Laverman <jjlaverman@web.de>"]
 license = "Apache-2.0"
diff --git a/pysolarfocus/__init__.py b/pysolarfocus/__init__.py
index 23b385c..b97b205 100644
--- a/pysolarfocus/__init__.py
+++ b/pysolarfocus/__init__.py
@@ -1,7 +1,8 @@
 """Python client lib for Solarfocus"""
-__version__ = "3.4.0"
+__version__ = "3.5.0"
 
 from enum import Enum
+from packaging import version
 
 #Default port for modbus
 PORT = 502
@@ -14,6 +15,10 @@ class Systems(str, Enum):
     Vampair = "Vampair"
     Therminator = "Therminator" 
     
+class ApiVersions(Enum):
+    V_21_140 = version.parse("21.140")
+    V_23_010 = version.parse("23.010")
+    
 from .modbus_wrapper import ModbusConnector
 from .component_factory import ComponentFactory
 from .const import SLAVE_ID
@@ -22,9 +27,13 @@ class SolarfocusAPI:
     """Solarfocus Heating System"""
     
     @property
-    def system(self): 
+    def system(self) -> Systems: 
         return self._system
     
+    @property
+    def api_version(self) -> ApiVersions: 
+        return self._api_version
+    
     def __init__(self,
                  ip:str,
                  heating_circuit_count:int = 1,
@@ -32,7 +41,8 @@ def __init__(self,
                  boiler_count:int = 1,
                  system:Systems=Systems.Vampair,
                  port:int=PORT,
-                 slave_id:int=SLAVE_ID):
+                 slave_id:int=SLAVE_ID,
+                 api_version:ApiVersions=ApiVersions.V_21_140):
         """Initialize Solarfocus communication."""
         assert heating_circuit_count >= 0 and heating_circuit_count < 9, "Heating circuit count must be between 0 and 8"
         assert buffer_count >= 0 and buffer_count < 5, "Buffer count must be between 0 and 4"
@@ -47,10 +57,11 @@ def __init__(self,
         #Single components
         self.heatpump = self.__factory.heatpump(system)
         self.photovoltaic = self.__factory.photovoltaic(system)
-        self.pelletsboiler = self.__factory.pelletsboiler(system)
+        self.pelletsboiler = self.__factory.pelletsboiler(system,api_version)
         self.solar = self.__factory.solar(system)
         self._slave_id = slave_id
         self._system = system
+        self._api_version = api_version
     
     def connect(self):
         """Connect to Solarfocus eco manager-touch"""
diff --git a/pysolarfocus/component_factory.py b/pysolarfocus/component_factory.py
index 61d2399..e71599a 100644
--- a/pysolarfocus/component_factory.py
+++ b/pysolarfocus/component_factory.py
@@ -6,7 +6,7 @@
 from .components.photovoltaic import *
 from .components.solar import *
 from .modbus_wrapper import ModbusConnector
-from . import Systems
+from . import Systems, ApiVersions
 
 
 class ComponentFactory:
@@ -53,8 +53,8 @@ def heatpump(self, system:Systems)->HeatPump:
     def photovoltaic(self, system:Systems)->Photovoltaic:
         return Photovoltaic()._initialize(self.__modbus_connector)
     
-    def pelletsboiler(self, system:Systems)->PelletsBoiler:
-        return PelletsBoiler()._initialize(self.__modbus_connector)
+    def pelletsboiler(self, system:Systems, api_version:ApiVersions)->PelletsBoiler:
+        return PelletsBoiler(api_version=api_version)._initialize(self.__modbus_connector)
     
     def solar(self, system:Systems)->Solar:
         return Solar()._initialize(self.__modbus_connector)
diff --git a/pysolarfocus/components/base/component.py b/pysolarfocus/components/base/component.py
index d14d344..c1d328b 100644
--- a/pysolarfocus/components/base/component.py
+++ b/pysolarfocus/components/base/component.py
@@ -1,10 +1,10 @@
 import logging
 
-from pysolarfocus.components.base.performance_calculator import PerformanceCalculator
 
 from ...modbus_wrapper import ModbusConnector
 from .data_value import DataValue
 from .enums import DataTypes, RegisterTypes
+from .performance_calculator import PerformanceCalculator
 from .register_slice import RegisterSlice
 
 
diff --git a/pysolarfocus/components/pellets_boiler.py b/pysolarfocus/components/pellets_boiler.py
index 6e88bef..a10ea5d 100644
--- a/pysolarfocus/components/pellets_boiler.py
+++ b/pysolarfocus/components/pellets_boiler.py
@@ -1,9 +1,14 @@
 from .base.component import Component
 from .base.enums import DataTypes, RegisterTypes
 from .base.data_value import DataValue
+from .. import ApiVersions
 
 class PelletsBoiler(Component):
-    def __init__(self,input_address=2400,holding_address=33400) -> None:
+    def __init__(self,input_address=2400,holding_address=-1,api_version:ApiVersions=ApiVersions.V_21_140) -> None:
+        
+        if api_version.value >= ApiVersions.V_23_010.value:
+            holding_address=33400
+        
         super().__init__(input_address, holding_address)
         self.temperature = DataValue(address=0,multiplier=0.1)
         self.status  = DataValue(address=1,type=DataTypes.UINT)
@@ -16,7 +21,9 @@ def __init__(self,input_address=2400,holding_address=33400) -> None:
         self.octoplus_buffer_temperature_bottom = DataValue(address=10,multiplier=0.1)
         self.octoplus_buffer_temperature_top = DataValue(address=11,multiplier=0.1)
         self.log_wood = DataValue(address=12,type=DataTypes.UINT)
-        self.pellet_usage_last_fill = DataValue(address=14,count=2,multiplier=0.1)
-        self.pellet_usage_total = DataValue(address=16,count=2,multiplier=0.1)
-        self.heat_energy_total = DataValue(address=18,count=2,multiplier=0.1)
-        self.pellet_usage_reset = DataValue(address=12,register_type=RegisterTypes.Holding)
\ No newline at end of file
+        
+        if api_version.value >= ApiVersions.V_23_010.value:
+            self.pellet_usage_last_fill = DataValue(address=14,count=2,multiplier=0.1)
+            self.pellet_usage_total = DataValue(address=16,count=2,multiplier=0.1)
+            self.heat_energy_total = DataValue(address=18,count=2,multiplier=0.1)
+            self.pellet_usage_reset = DataValue(address=12,register_type=RegisterTypes.Holding)
\ No newline at end of file