diff --git a/sentio_prober_control/Sentio/CommandGroups/ProbeCommandGroup.py b/sentio_prober_control/Sentio/CommandGroups/ProbeCommandGroup.py
index 14ae177..7bdc897 100644
--- a/sentio_prober_control/Sentio/CommandGroups/ProbeCommandGroup.py
+++ b/sentio_prober_control/Sentio/CommandGroups/ProbeCommandGroup.py
@@ -124,6 +124,11 @@ def get_probe_site(self, probe: ProbePosition, idx: int) -> Tuple[str, float, fl
         Returns:
             A tuple containing the site index, position x, the position y in micrometer and the reference.
         """
+        
+        # This command was briefly removed and is not part of the SENTIO 24.0
+        # release. It was reintroduced in 25.1.
+        Compatibility.assert_min(CompatibilityLevel.Sentio_25_1)
+
         self.comm.send(f"get_positioner_site {probe.to_string()},{idx}")
         resp = Response.check_resp(self.comm.read_line())
         tok = resp.message().split(",")
diff --git a/sentio_prober_control/Sentio/Compatibility.py b/sentio_prober_control/Sentio/Compatibility.py
index 7ecfba0..988eaa9 100644
--- a/sentio_prober_control/Sentio/Compatibility.py
+++ b/sentio_prober_control/Sentio/Compatibility.py
@@ -8,9 +8,13 @@ class CompatibilityLevel(IntEnum):
         It is used to determine which features are available in the prober. This enum
         only contains SENTIO versions which introduces API changes.
     """
+    # Undefined compatibility level, used for prober instances that are not yet initialized.
+    # Do NOT use this value in your code production code. It is signalling an uninitialized 
+    # state.
     Auto = 0
-    Sentio_24 = 1
-    Sentio_25_2 = 2
+    Sentio_24_0 = 1
+    Sentio_25_1 = 2
+    Sentio_25_2 = 3
     Experimental = 99
 
 
@@ -36,4 +40,4 @@ def assert_min(level : CompatibilityLevel) -> None:
             RuntimeError: If the current compatibility level is lower than the required level.
         """
         if Compatibility.level < level:
-            raise RuntimeError(f"Compatibility level {Compatibility.level} is lower than required {level}.")
\ No newline at end of file
+            raise RuntimeError(f"This command is not supported by your machine! The machine reports a compatibility level of {Compatibility.level.name} but {level.name} is required to execute the command.")
\ No newline at end of file
diff --git a/sentio_prober_control/Sentio/ProberSentio.py b/sentio_prober_control/Sentio/ProberSentio.py
index 913229a..5ca74bd 100644
--- a/sentio_prober_control/Sentio/ProberSentio.py
+++ b/sentio_prober_control/Sentio/ProberSentio.py
@@ -118,17 +118,24 @@ def __init__(self, comm: CommunicatorBase, compat_level : CompatibilityLevel = C
                 major = int(parts[0]) if len(parts) > 0 else None
                 minor = int(parts[1]) if len(parts) > 1 else None
                 release = int(parts[2]) if len(parts) > 2 else None
-                if major==25 and (minor==2 or (minor==1 and release==99)):
+                if major==25 and (minor==1 or (minor==0 and release==99)):
+                    Compatibility.level = CompatibilityLevel.Sentio_25_1
+                elif major==25 and (minor==2 or (minor==1 and release==99)):
                     Compatibility.level = CompatibilityLevel.Sentio_25_2
                 else:
-                    Compatibility.level = CompatibilityLevel.Sentio_24
+                    Compatibility.level = CompatibilityLevel.Sentio_24_0
+
+        # make sure there is a valid compatibility level now
+        assert Compatibility.level != CompatibilityLevel.Auto, "Compatibility level could not be determined. Please set it manually."
 
         #
         # More command groups not supported by all SENTIO versions.
         #
         
-        # The probe command group has optional sub-groups for top and bottom probes.
-        # These are only available for Sentio > 25.2
+        # The probe command group has optional sub-groups for top and bottom 
+        # probes. These are only available for Sentio > 25.2. Therefore 
+        # this command group must be initialized after determining the 
+        # compatibility level.
         self.probe: ProbeCommandGroup = ProbeCommandGroup(self)
 
         # Command groups for stages; Only available for Sentio > 25.2
@@ -482,7 +489,8 @@ def get_scope_z(self) -> float:
     def get_scope_site(self, idx : int) -> Tuple[str, float, float, bool]:
         """ Get scope site data.
 
-            This command queries the name and position of a scope site. The index is zero based.
+            This command queries the name and position of a scope site. The index 
+            is zero based.
 
         Args:
             idx (int): The index of the site to query.
@@ -491,6 +499,10 @@ def get_scope_site(self, idx : int) -> Tuple[str, float, float, bool]:
             num (int): The number of defined scope sites.
         """
 
+        # This command was briefly removed and is not part of the SENTIO 24.0
+        # release. It was reintroduced in 25.2.
+        Compatibility.assert_min(CompatibilityLevel.Sentio_25_2)
+
         self.comm.send(f"get_scope_site {idx}")
         resp = Response.check_resp(self.comm.read_line())
         tok = resp.message().split(",")