diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 642e98a..e5abf36 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -2,6 +2,13 @@ Changelog
 =========
 
 
+2.1.2 (2025-11-15)
+-------------------
+
+- fix: exceptions not frozen dataclasses anymore (cause errors in pytest).
+- fix: '.' replaced by '_' in openapi model prefix.
+
+
 2.1.1 (2025-11-08)
 -------------------
 
diff --git a/pjrpc/client/exceptions.py b/pjrpc/client/exceptions.py
index e3dd4fa..a0ccca2 100644
--- a/pjrpc/client/exceptions.py
+++ b/pjrpc/client/exceptions.py
@@ -20,7 +20,7 @@
 ]
 
 
-@dc.dataclass(frozen=True)
+@dc.dataclass
 class JsonRpcError(exceptions.JsonRpcError):
     """
     Client JSON-RPC error.
diff --git a/pjrpc/common/exceptions.py b/pjrpc/common/exceptions.py
index 115efdd..97cccef 100644
--- a/pjrpc/common/exceptions.py
+++ b/pjrpc/common/exceptions.py
@@ -35,7 +35,7 @@ class DeserializationError(ProtocolError, ValueError):
     """
 
 
-@dc.dataclass(frozen=True)
+@dc.dataclass
 class JsonRpcError(BaseError):
     """
     `JSON-RPC <https://www.jsonrpc.org>`_ protocol error.
diff --git a/pjrpc/server/exceptions.py b/pjrpc/server/exceptions.py
index 1474c98..760a63f 100644
--- a/pjrpc/server/exceptions.py
+++ b/pjrpc/server/exceptions.py
@@ -20,7 +20,7 @@
 ]
 
 
-@dc.dataclass(frozen=True)
+@dc.dataclass
 class JsonRpcError(exceptions.JsonRpcError):
     """
     Server JSON-RPC error.
diff --git a/pjrpc/server/specs/openapi/__init__.py b/pjrpc/server/specs/openapi/__init__.py
index 73168b2..e1fb91d 100644
--- a/pjrpc/server/specs/openapi/__init__.py
+++ b/pjrpc/server/specs/openapi/__init__.py
@@ -352,7 +352,7 @@ def _extract_errors_schema(
     ) -> tuple[dict[int, dict[str, Any]], dict[str, JsonSchema]]:
         status_error_schema_map: dict[int, dict[str, Any]] = {}
         component_schemas: dict[str, JsonSchema] = {}
-        component_name_prefix = method_metadata.component_name_prefix or f"{method.__module__}_"
+        component_name_prefix = method_metadata.component_name_prefix or f"{method.__module__.replace('.', '_')}_"
 
         for status, errors in status_errors_map.items():
             if result := self._extractor.extract_error_response_schema(
@@ -378,7 +378,7 @@ def _extract_request_schema(
         method_metadata: MethodMetadata,
     ) -> tuple[MaybeSet[dict[str, Any]], dict[str, JsonSchema]]:
         component_schemas: dict[str, JsonSchema] = {}
-        component_name_prefix = method_metadata.component_name_prefix or f"{method.__module__}_"
+        component_name_prefix = method_metadata.component_name_prefix or f"{method.__module__.replace('.', '_')}_"
 
         request_schema: MaybeSet[dict[str, Any]] = UNSET
         if params_schema := method_metadata.params_schema:
@@ -406,7 +406,7 @@ def _extract_response_schema(
         errors: list[type[exceptions.TypedError]],
     ) -> tuple[MaybeSet[dict[str, Any]], dict[str, JsonSchema]]:
         component_schemas: dict[str, JsonSchema] = {}
-        component_name_prefix = method_metadata.component_name_prefix or f"{method.__module__}_"
+        component_name_prefix = method_metadata.component_name_prefix or f"{method.__module__.replace('.', '_')}_"
 
         response_schema: MaybeSet[dict[str, Any]] = UNSET
         if result_schema := method_metadata.result_schema:
diff --git a/pyproject.toml b/pyproject.toml
index b3efc3b..20a727d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pjrpc"
-version = "2.1.1"
+version = "2.1.2"
 description = "Extensible JSON-RPC library"
 authors = ["Dmitry Pershin <dapper1291@gmail.com>"]
 license = "Unlicense"