diff --git a/HABApp/__version__.py b/HABApp/__version__.py
index 44c2d02a..bb67aeb6 100644
--- a/HABApp/__version__.py
+++ b/HABApp/__version__.py
@@ -1 +1 @@
-__version__ = '0.15.0'
+__version__ = '0.15.1'
diff --git a/HABApp/core/logger.py b/HABApp/core/logger.py
index c9b4677b..6cfa3261 100644
--- a/HABApp/core/logger.py
+++ b/HABApp/core/logger.py
@@ -37,9 +37,12 @@ def add(self, text: str, *args, **kwargs):
         self.lines.append(text.format(*args, **kwargs))
         return self
 
-    def add_exception(self, e: Exception):
-        for line in str(e).splitlines():
-            self.lines.append(line)
+    def add_exception(self, e: Exception, add_traceback: bool = False):
+        if not add_traceback:
+            for line in str(e).splitlines():
+                self.lines.append(line)
+        else:
+            self.lines.extend(HABApp.core.wrapper.format_exception(e))
         return self
 
     def dump(self) -> bool:
diff --git a/HABApp/openhab/connection_handler/func_async.py b/HABApp/openhab/connection_handler/func_async.py
index 6f22999f..3ff617d4 100644
--- a/HABApp/openhab/connection_handler/func_async.py
+++ b/HABApp/openhab/connection_handler/func_async.py
@@ -192,6 +192,8 @@ async def async_set_thing_cfg(uid: str, cfg: typing.Dict[str, typing.Any]):
     elif ret.status >= 300:
         raise ValueError('Something went wrong')
 
+    return ret.status
+
 
 # ---------------------------------------------------------------------------------------------------------------------
 # Link handling is experimental
diff --git a/HABApp/parameters/parameter.py b/HABApp/parameters/parameter.py
index 0007295f..53ecebd5 100644
--- a/HABApp/parameters/parameter.py
+++ b/HABApp/parameters/parameter.py
@@ -1,4 +1,5 @@
 import typing
+from math import ceil, floor
 
 from .parameters import add_parameter as _add_parameter
 from .parameters import get_value as _get_value
@@ -29,6 +30,9 @@ def value(self) -> typing.Any:
         """
         return _get_value(self.filename, *self.keys)
 
+    def __repr__(self):
+        return f'<Parameter file: {self.filename}, keys: {self.keys}, value: {self.value}'
+
     def __bool__(self):
         return bool(self.value)
 
@@ -36,28 +40,134 @@ def __eq__(self, other):
         return self.value == other
 
     def __lt__(self, other):
-        if not isinstance(other, (int, float)):
-            return NotImplemented
-
         return self.value < other
 
     def __le__(self, other):
-        if not isinstance(other, (int, float)):
-            return NotImplemented
-
         return self.value <= other
 
     def __ge__(self, other):
-        if not isinstance(other, (int, float)):
-            return NotImplemented
-
         return self.value >= other
 
     def __gt__(self, other):
-        if not isinstance(other, (int, float)):
-            return NotImplemented
-
         return self.value > other
 
-    def __repr__(self):
-        return f'<Parameter file: {self.filename}, keys: {self.keys}, value: {self.value}'
+    # https://docs.python.org/3/reference/datamodel.html#emulating-numeric-types
+    # These methods are called to implement the binary arithmetic operations
+    def __add__(self, other):
+        return self.value.__add__(other)
+
+    def __sub__(self, other):
+        return self.value.__sub__(other)
+
+    def __mul__(self, other):
+        return self.value.__mul__(other)
+
+    def __matmul__(self, other):
+        return self.value.__matmul__(other)
+
+    def __truediv__(self, other):
+        return self.value.__truediv__(other)
+
+    def __floordiv__(self, other):
+        return self.value.__floordiv__(other)
+
+    def __mod__(self, other):
+        return self.value.__mod__(other)
+
+    def __divmod__(self, other):
+        return self.value.__divmod__(other)
+
+    def __pow__(self, other):
+        return self.value.__pow__(other)
+
+    def __lshift__(self, other):
+        return self.value.__lshift__(other)
+
+    def __rshift__(self, other):
+        return self.value.__rshift__(other)
+
+    def __and__(self, other):
+        return self.value.__and__(other)
+
+    def __xor__(self, other):
+        return self.value.__xor__(other)
+
+    def __or__(self, other):
+        return self.value.__or__(other)
+
+    # Unary arithmetic operations (-, +, abs() and ~).
+    def __neg__(self):
+        return self.value.__neg__()
+
+    def __pos__(self):
+        return self.value.__pos__()
+
+    def __abs__(self):
+        return self.value.__abs__()
+
+    def __invert__(self):
+        return self.value.__invert__()
+
+    # built-in functions complex(), int() and float().
+    def __complex__(self):
+        return self.value.__complex__()
+
+    def __int__(self):
+        return self.value.__int__()
+
+    def __float__(self):
+        return self.value.__float__()
+
+    # built-in function round() and math functions trunc(), floor() and ceil().
+    def __round__(self, ndigits=None):
+        return self.value.__round__(ndigits)
+
+    def __trunc__(self):
+        return self.value.__trunc__()
+
+    def __floor__(self):
+        return floor(self.value)
+
+    def __ceil__(self):
+        return ceil(self.value)
+
+    # we don't support modification in place! We have to override this because otherwise
+    # python falls back to the methods above
+    def __iadd__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __isub__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __imul__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __imatmul__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __itruediv__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __ifloordiv__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __imod__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __ipow__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __ilshift__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __irshift__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __iand__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __ixor__(self, other):
+        return PermissionError('Parameter can not be changed!')
+
+    def __ior__(self, other):
+        return PermissionError('Parameter can not be changed!')
diff --git a/HABApp/parameters/parameter_files.py b/HABApp/parameters/parameter_files.py
index f7caf52b..832afe1e 100644
--- a/HABApp/parameters/parameter_files.py
+++ b/HABApp/parameters/parameter_files.py
@@ -1,6 +1,5 @@
 import logging
 import threading
-import traceback
 
 import ruamel.yaml
 
@@ -54,10 +53,11 @@ def load_file(event: HABApp.core.events.habapp_events.RequestFileLoadEvent):
             if data is None:
                 data = {}
             set_parameter_file(path.stem, data)
-        except Exception:
-            log.error(f"Could not load params from {path.name}!")
-            for line in traceback.format_exc().splitlines():
-                log.error(line)
+        except Exception as exc:
+            e = HABApp.core.logger.HABAppError(log)
+            e.add(f"Could not load params from {path.name}!")
+            e.add_exception(exc, add_traceback=True)
+            e.dump()
             return None
 
         log.debug(f'Loaded params from {path.name}!')
@@ -69,10 +69,11 @@ def unload_file(event: HABApp.core.events.habapp_events.RequestFileUnloadEvent):
     with LOCK:  # serialize to get proper error messages
         try:
             remove_parameter_file(path.stem)
-        except Exception:
-            log.error(f"Could not remove parameters from {path.name}!")
-            for line in traceback.format_exc().splitlines():
-                log.error(line)
+        except Exception as exc:
+            e = HABApp.core.logger.HABAppError(log)
+            e.add(f"Could not remove parameters from {path.name}!")
+            e.add_exception(exc, add_traceback=True)
+            e.dump()
             return None
 
         log.debug(f'Removed params from {path.name}!')
diff --git a/_doc/getting_started.rst b/_doc/getting_started.rst
index c17a67f9..537f7468 100644
--- a/_doc/getting_started.rst
+++ b/_doc/getting_started.rst
@@ -76,8 +76,10 @@ This often comes in handy if there is some logic that shall be applied to differ
 
 Interacting with items
 ------------------------------
-Iterating with items is done through the Item factory methods.
-Posting values will automatically create the corresponding events on the event bus.
+Iterating with items is done through the corresponding Item factory methods.
+Posting values will automatically create the events on the event bus.
+This example will create an item in HABApp (locally) and post some updates to it.
+To access items from openhab use the correct openhab item type (see :ref:`the openhab item description <OPENHAB_ITEM_TYPES>`).
 
 .. execute_code::
     :header_output: Output
@@ -166,10 +168,12 @@ It is possible to watch items for changes or updates.
 
         # the function has 1 argument which is the event
         def item_changed(self, event: ValueChangeEvent):
-            print(f'{event.name} changed from {event.old_value} to {event.value}')
+            print(f'{event.name} changed from "{event.old_value}" to "{event.value}"')
+            print(f'Last change of {self.my_item.name}: {self.my_item.last_change}')
 
         def item_updated(self, event: ValueUpdateEvent):
-            print(f'{event.name} updated value: {event.value}')
+            print(f'{event.name} updated value: "{event.value}"')
+            print(f'Last update of {self.my_item.name}: {self.my_item.last_update}')
 
     MyFirstRule()
     # hide
diff --git a/_doc/interface_openhab.rst b/_doc/interface_openhab.rst
index c0621d38..79d05819 100644
--- a/_doc/interface_openhab.rst
+++ b/_doc/interface_openhab.rst
@@ -18,6 +18,7 @@ Function parameters
    :imported-members:
 
 
+.. _OPENHAB_ITEM_TYPES:
 
 Openhab item types
 ------------------------------
@@ -37,6 +38,7 @@ Example:
     HABApp.core.Items.set_item(ContactItem('MyContact', initial_value='OPEN'))
     HABApp.core.Items.set_item(SwitchItem('MySwitch', initial_value='OFF'))
     # hide
+    from HABApp.openhab.items import ContactItem, SwitchItem
 
     my_contact = ContactItem.get_item('MyContact')
     if my_contact.is_open():
@@ -225,6 +227,8 @@ and how to automatically link items to it.
 .. tip::
    Integer values can be specified either as integer (``20``) or hex (``0x14``)
 
+The entries ``thing config``, ``create items`` and ``channels`` are optional and can be combined as desired.
+
 
 .. code-block:: yaml
 
@@ -236,7 +240,8 @@ and how to automatically link items to it.
    filter:
      thing_type: zwave:philio_pst02a_00_000
 
-   # Set this configuration for all things.
+   # Set this configuration every matching thing. HABApp will automatically only 
+   # change the values which are not already correct.
    # Here it is the z-wave parameters which are responsible for the device behaviour
    thing config:
      4: 99     # Light Threshold
diff --git a/readme.md b/readme.md
index fd6d638b..d92f6e96 100644
--- a/readme.md
+++ b/readme.md
@@ -2,6 +2,13 @@
 [![Build Status](https://travis-ci.org/spacemanspiff2007/HABApp.svg?branch=master)](https://travis-ci.org/spacemanspiff2007/HABApp)
 [![Documentation Status](https://readthedocs.org/projects/habapp/badge/?version=latest)](https://habapp.readthedocs.io/en/latest/?badge=latest)
 [![Updates](https://pyup.io/repos/github/spacemanspiff2007/HABApp/shield.svg)](https://pyup.io/repos/github/spacemanspiff2007/HABApp/)
+![PyPI - Python Version](https://img.shields.io/pypi/pyversions/habapp)
+
+![PyPI](https://img.shields.io/pypi/v/HABapp)
+[![Downloads](https://pepy.tech/badge/habapp/month)](https://pepy.tech/project/habapp/month)
+![Docker Image Version (latest by date)](https://img.shields.io/docker/v/spacemanspiff2007/habapp?label=docker)
+![Docker Pulls](https://img.shields.io/docker/pulls/spacemanspiff2007/habapp)
+
 
 _Easy automation with MQTT and/or openHAB_
 
@@ -92,4 +99,4 @@ class MyOpenhabRule(HABApp.Rule):
         self.oh.post_update('TestItemUpdate', 123)
 
 MyOpenhabRule()
-```
\ No newline at end of file
+```
diff --git a/tests/test_core/test_logger.py b/tests/test_core/test_logger.py
index bcdec5b5..ad9d0bcd 100644
--- a/tests/test_core/test_logger.py
+++ b/tests/test_core/test_logger.py
@@ -12,6 +12,11 @@ def test_exception_multiline():
     assert HABAppLogger(None).add_exception(e).lines == ['Line1', 'Line2', 'Line3']
 
 
+def test_exception_traceback():
+    e = Exception('Line1\nLine2\nLine3')
+    assert HABAppLogger(None).add_exception(e, add_traceback=True).lines == ['Exception: Line1', 'Line2', 'Line3']
+
+
 def test_bool():
     for cls in (HABAppError, HABAppInfo, HABAppWarning):
         i = cls(getLogger('test')).add('')
diff --git a/tests/test_rule/test_rule_params.py b/tests/test_rule/test_rule_params.py
index 7a15383a..997fbedd 100644
--- a/tests/test_rule/test_rule_params.py
+++ b/tests/test_rule/test_rule_params.py
@@ -66,6 +66,22 @@ def test_float_operators(params):
     assert p > 4
 
 
+def test_arithmetic(params):
+    Parameters.set_parameter_file('file', {'key': 1})
+    p = Parameter('file', 'key')
+
+    assert int(p) == 1
+    assert p + 1 == 2
+    assert p - 1 == 0
+    assert p * 3 == 3
+    assert p / 2 == 0.5
+    assert p // 2 == 0
+    assert p << 1 == 2
+    assert p >> 1 == 0
+    assert p | 2 == 3
+    assert p & 2 == 0
+
+
 def test_simple_key_creation(params):
 
     Parameter('file', 'key')