diff --git a/Dockerfile b/Dockerfile
index 27455bb..4a0d367 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,6 @@
 ARG img_user=ghcr.io/driplineorg
 ARG img_repo=dripline-python
-#ARG img_tag=develop-dev
-ARG img_tag=receiver-test
+ARG img_tag=v5.0.0-dev
 
 FROM ${img_user}/${img_repo}:${img_tag}
 
diff --git a/dripline/extensions/__init__.py b/dripline/extensions/__init__.py
index e9cb836..f016cc8 100644
--- a/dripline/extensions/__init__.py
+++ b/dripline/extensions/__init__.py
@@ -8,5 +8,7 @@
 # Modules in this directory
 
 from .add_auth_spec import *
+from .cmd_endpoint import *
+from .asteval_endpoint import *
 from .thermo_fisher_endpoint import *
 from .ethernet_thermo_fisher_service import *
diff --git a/dripline/extensions/asteval_endpoint.py b/dripline/extensions/asteval_endpoint.py
new file mode 100644
index 0000000..93df946
--- /dev/null
+++ b/dripline/extensions/asteval_endpoint.py
@@ -0,0 +1,40 @@
+import asteval # used for FormatEntity
+import re # used for FormatEntity
+
+from dripline.core import calibrate, ThrowReply
+from dripline.implementations import FormatEntity
+
+import logging
+logger = logging.getLogger(__name__)
+
+__all__ = []
+
+
+
+__all__.append('AstevalFormatEntity')
+class AstevalFormatEntity(FormatEntity):
+    '''
+    Utility Entity allowing arbitrary set and query syntax and formatting for more complicated usage cases
+    No assumption about SCPI communication syntax.
+    '''
+
+    def __init__(self,
+                 asteval_format_response_string="def f(response): return response",
+                 **kwargs):
+        '''
+        Args:
+            asteval_format_response_string (str): function definition to format response. Default: "def f(response): return response"
+            *kwargs -> FormatEntity
+        '''
+        FormatEntity.__init__(self, **kwargs)
+        self.asteval_format_response_string = asteval_format_response_string # has to contain a definition "def f(response): ... return value"
+        logger.debug(f'asteval_format_response_string: {repr(self.asteval_format_response_string)}')
+        self.evaluator(asteval_format_response_string)
+
+    @calibrate()
+    def on_get(self):
+        result =FormatEntity.on_get(self)
+        raw = result["value_raw"]
+        processed_result = self.evaluator(f"f('{raw}')")
+        logger.debug(f"processed_result: {repr(processed_result)}")
+        return processed_result
diff --git a/dripline/extensions/cmd_endpoint.py b/dripline/extensions/cmd_endpoint.py
new file mode 100644
index 0000000..7524dda
--- /dev/null
+++ b/dripline/extensions/cmd_endpoint.py
@@ -0,0 +1,31 @@
+import re # used for FormatEntity
+
+from dripline.core import calibrate, ThrowReply
+from dripline.core import Entity
+
+import logging
+logger = logging.getLogger(__name__)
+
+__all__ = []
+
+__all__.append('CmdEntity')
+class CmdEntity(Entity):
+    '''
+    SCPI Entity to execute a command, instead of a get or set.
+    The command is given via "cmd_str" and takes no additional arguments. 
+    This can e.g. be used to auto-calibrate, set to zero or similar device commands.
+    '''
+    def __init__(self, cmd_str=None, **kwargs):
+        '''
+        Args:
+            cmd_str (str): sent verbatim in the event of cmd().
+        '''
+        Entity.__init__(self, **kwargs)
+        logger.debug(f"I get cmd_str: {cmd_str}, which is of type {type(cmd_str)}.")
+        if cmd_str is None:
+            raise ValueError("cmd_str is required for CmdEntity")
+        self.cmd_str = cmd_str
+
+    def cmd(self):
+        logger.debug("Command function was successfully called")
+        return self.service.send_to_device([self.cmd_str])