allow rasa to run without interruption when model is outdated

rasa/core/interpreter.py

@@ -37,7 +37,12 @@ def create(
         if isinstance(obj, NaturalLanguageInterpreter):
             return obj
         elif isinstance(obj, str) and os.path.exists(obj):
-            return RasaNLUInterpreter(model_directory=obj)
+            from rasa.nlu.model import UnsupportedModelError
+            try:
+                return RasaNLUInterpreter(model_directory=obj)
+            except UnsupportedModelError as e:
+                logger.warning(e.message)
+                return RegexInterpreter()
         elif isinstance(obj, str) and not os.path.exists(obj):
             # user passed in a string, but file does not exist
             logger.warning(

rasa/core/policies/ensemble.py

@@ -318,11 +318,15 @@ def _ensure_loaded_policy(cls, policy, policy_cls, policy_name: Text):
             )
 
     @classmethod
-    def load(cls, path: Text) -> "PolicyEnsemble":
+    def load(cls, path: Text) -> Optional["PolicyEnsemble"]:
         """Loads policy and domain specification from storage"""
 
         metadata = cls.load_metadata(path)
-        cls.ensure_model_compatibility(metadata)
+        try:
+            cls.ensure_model_compatibility(metadata)
+        except UnsupportedDialogueModelError as e:
+            logger.warning(e.message)
+            return None
         policies = []
         for i, policy_name in enumerate(metadata["policy_names"]):
             policy_cls = registry.policy_from_module_path(policy_name)