diff --git a/src/fish_audio_sdk/schemas.py b/src/fish_audio_sdk/schemas.py
index 81d6323..af40743 100644
--- a/src/fish_audio_sdk/schemas.py
+++ b/src/fish_audio_sdk/schemas.py
@@ -6,7 +6,7 @@
 
 from pydantic import BaseModel, Field
 
-Backends = Literal["speech-1.5", "speech-1.6", "agent-x0", "s1", "s1-mini"]
+Backends = Literal["speech-1.5", "speech-1.6", "agent-x0", "s1", "s1-mini", "s2-pro"]
 
 Item = TypeVar("Item")
 
diff --git a/src/fishaudio/resources/tts.py b/src/fishaudio/resources/tts.py
index 3ec2343..0167ce6 100644
--- a/src/fishaudio/resources/tts.py
+++ b/src/fishaudio/resources/tts.py
@@ -28,6 +28,7 @@
     TTSConfig,
     TTSRequest,
 )
+from fishaudio.types.shared import warn_if_deprecated_model
 
 from .realtime import aiter_websocket_audio, iter_websocket_audio
 
@@ -81,7 +82,7 @@ def stream(
         latency: Optional[LatencyMode] = None,
         speed: Optional[float] = None,
         config: TTSConfig = TTSConfig(),
-        model: Model = "s1",
+        model: Model = "s2-pro",
         request_options: Optional[RequestOptions] = None,
     ) -> AudioStream:
         """
@@ -115,6 +116,8 @@ def stream(
             audio = client.tts.stream(text="Hello world").collect()
             ```
         """
+        warn_if_deprecated_model(model)
+
         # Build request payload from config
         request = _config_to_tts_request(config, text)
 
@@ -163,7 +166,7 @@ def convert(
         latency: Optional[LatencyMode] = None,
         speed: Optional[float] = None,
         config: TTSConfig = TTSConfig(),
-        model: Model = "s1",
+        model: Model = "s2-pro",
         request_options: Optional[RequestOptions] = None,
     ) -> bytes:
         """
@@ -225,7 +228,7 @@ def stream_websocket(
         latency: Optional[LatencyMode] = None,
         speed: Optional[float] = None,
         config: TTSConfig = TTSConfig(),
-        model: Model = "s1",
+        model: Model = "s2-pro",
         max_workers: int = 10,
         ws_options: Optional[WebSocketOptions] = None,
     ) -> Iterator[bytes]:
@@ -310,6 +313,8 @@ def text_generator():
                     f.write(audio_chunk)
             ```
         """
+        warn_if_deprecated_model(model)
+
         # Build TTSRequest from config
         tts_request = _config_to_tts_request(config, text="")
 
@@ -381,7 +386,7 @@ async def stream(
         latency: Optional[LatencyMode] = None,
         speed: Optional[float] = None,
         config: TTSConfig = TTSConfig(),
-        model: Model = "s1",
+        model: Model = "s2-pro",
         request_options: Optional[RequestOptions] = None,
     ) -> AsyncAudioStream:
         """
@@ -416,6 +421,8 @@ async def stream(
             audio = await stream.collect()
             ```
         """
+        warn_if_deprecated_model(model)
+
         # Build request payload from config
         request = _config_to_tts_request(config, text)
 
@@ -464,7 +471,7 @@ async def convert(
         latency: Optional[LatencyMode] = None,
         speed: Optional[float] = None,
         config: TTSConfig = TTSConfig(),
-        model: Model = "s1",
+        model: Model = "s2-pro",
         request_options: Optional[RequestOptions] = None,
     ) -> bytes:
         """
@@ -527,7 +534,7 @@ async def stream_websocket(
         latency: Optional[LatencyMode] = None,
         speed: Optional[float] = None,
         config: TTSConfig = TTSConfig(),
-        model: Model = "s1",
+        model: Model = "s2-pro",
         ws_options: Optional[WebSocketOptions] = None,
     ):
         """
@@ -610,6 +617,8 @@ async def text_generator():
                     await f.write(audio_chunk)
             ```
         """
+        warn_if_deprecated_model(model)
+
         # Build TTSRequest from config
         tts_request = _config_to_tts_request(config, text="")
 
diff --git a/src/fishaudio/types/shared.py b/src/fishaudio/types/shared.py
index 427d5da..879a012 100644
--- a/src/fishaudio/types/shared.py
+++ b/src/fishaudio/types/shared.py
@@ -1,5 +1,6 @@
 """Shared types used across the SDK."""
 
+import warnings
 from typing import Generic, Literal, TypeVar
 
 from pydantic import BaseModel
@@ -21,7 +22,21 @@ class PaginatedResponse(BaseModel, Generic[T]):
 
 
 # Model types
-Model = Literal["speech-1.5", "speech-1.6", "s1"]
+Model = Literal["speech-1.5", "speech-1.6", "s1", "s2-pro"]
+
+# Deprecated models
+DEPRECATED_MODELS = {"speech-1.5", "speech-1.6"}
+
+
+def warn_if_deprecated_model(model: str) -> None:
+    """Emit a deprecation warning if a legacy model is used."""
+    if model in DEPRECATED_MODELS:
+        warnings.warn(
+            f"Model '{model}' is deprecated. Use 's1' or 's2-pro' instead.",
+            DeprecationWarning,
+            stacklevel=3,
+        )
+
 
 # Audio format types
 AudioFormat = Literal["wav", "pcm", "mp3", "opus"]
diff --git a/tests/integration/test_tts_integration.py b/tests/integration/test_tts_integration.py
index 19e511a..5d4e91e 100644
--- a/tests/integration/test_tts_integration.py
+++ b/tests/integration/test_tts_integration.py
@@ -45,6 +45,7 @@ def test_tts_with_prosody(self, client, save_audio):
         # Write to output directory
         save_audio(audio, "test_prosody.mp3")
 
+    @pytest.mark.filterwarnings("ignore::DeprecationWarning")
     def test_tts_with_different_models(self, client, save_audio):
         """Test TTS with different models."""
         models = get_args(Model)
diff --git a/tests/integration/test_tts_websocket_integration.py b/tests/integration/test_tts_websocket_integration.py
index 1dc1604..ee9aa15 100644
--- a/tests/integration/test_tts_websocket_integration.py
+++ b/tests/integration/test_tts_websocket_integration.py
@@ -6,7 +6,7 @@
 
 from fishaudio import WebSocketOptions
 from fishaudio.types import FlushEvent, Prosody, TextEvent, TTSConfig
-from fishaudio.types.shared import Model
+from fishaudio.types.shared import DEPRECATED_MODELS, Model
 
 from .conftest import TEST_REFERENCE_ID
 
@@ -35,6 +35,7 @@ def text_stream():
         # Save the audio
         save_audio(audio_chunks, "test_websocket_streaming.mp3")
 
+    @pytest.mark.filterwarnings("ignore::DeprecationWarning")
     @pytest.mark.parametrize(
         "model",
         [
@@ -44,7 +45,7 @@ def text_stream():
                     reason="WebSocket unreliable for legacy models"
                 ),
             )
-            if not m.startswith("s1")
+            if m in DEPRECATED_MODELS
             else m
             for m in get_args(Model)
         ],
@@ -137,16 +138,14 @@ def text_stream():
         save_audio(audio_chunks, "test_websocket_reference.mp3")
 
     def test_websocket_streaming_empty_text(self, client, save_audio):
-        """Test WebSocket streaming with empty text stream raises error."""
-        from fishaudio.exceptions import WebSocketError
+        """Test WebSocket streaming with empty text stream completes without error."""
 
         def text_stream():
             return
             yield  # Make it a generator
 
-        # Empty stream should raise WebSocketError as API returns error
-        with pytest.raises(WebSocketError, match="WebSocket stream ended with error"):
-            list(client.tts.stream_websocket(text_stream()))
+        audio_chunks = list(client.tts.stream_websocket(text_stream()))
+        assert isinstance(audio_chunks, list)
 
     def test_websocket_very_long_generation_with_timeout(self, client, save_audio):
         """
@@ -223,6 +222,7 @@ async def text_stream():
 
         save_audio(audio_chunks, "test_async_websocket_streaming.mp3")
 
+    @pytest.mark.filterwarnings("ignore::DeprecationWarning")
     @pytest.mark.asyncio
     @pytest.mark.parametrize(
         "model",
@@ -233,7 +233,7 @@ async def text_stream():
                     reason="WebSocket unreliable for legacy models"
                 ),
             )
-            if not m.startswith("s1")
+            if m in DEPRECATED_MODELS
             else m
             for m in get_args(Model)
         ],
@@ -366,14 +366,13 @@ async def text_stream():
 
     @pytest.mark.asyncio
     async def test_async_websocket_streaming_empty_text(self, async_client, save_audio):
-        """Test async WebSocket streaming with empty text stream raises error."""
-        from fishaudio.exceptions import WebSocketError
+        """Test async WebSocket streaming with empty text stream completes without error."""
 
         async def text_stream():
             return
             yield  # Make it an async generator
 
-        # Empty stream should raise WebSocketError as API returns error
-        with pytest.raises(WebSocketError, match="WebSocket stream ended with error"):
-            async for chunk in async_client.tts.stream_websocket(text_stream()):
-                pass
+        audio_chunks = []
+        async for chunk in async_client.tts.stream_websocket(text_stream()):
+            audio_chunks.append(chunk)
+        assert isinstance(audio_chunks, list)
diff --git a/tests/unit/test_tts.py b/tests/unit/test_tts.py
index de62520..132038a 100644
--- a/tests/unit/test_tts.py
+++ b/tests/unit/test_tts.py
@@ -63,7 +63,7 @@ def test_stream_basic(self, tts_client, mock_client_wrapper):
 
         # Check headers
         assert call_args[1]["headers"]["Content-Type"] == "application/msgpack"
-        assert call_args[1]["headers"]["model"] == "s1"  # default model
+        assert call_args[1]["headers"]["model"] == "s2-pro"  # default model
 
         # Check payload was msgpack encoded
         assert "content" in call_args[1]
diff --git a/tests/unit/test_tts_realtime.py b/tests/unit/test_tts_realtime.py
index eaf9210..c3b60a9 100644
--- a/tests/unit/test_tts_realtime.py
+++ b/tests/unit/test_tts_realtime.py
@@ -93,6 +93,7 @@ def test_stream_websocket_basic(
             mock_connect_ws.assert_called_once()
             assert mock_connect_ws.call_args[0][0] == "/v1/tts/live"
 
+    @pytest.mark.filterwarnings("ignore::DeprecationWarning")
     @patch("fishaudio.resources.tts.connect_ws")
     @patch("fishaudio.resources.tts.ThreadPoolExecutor")
     def test_stream_websocket_with_config(
@@ -425,6 +426,7 @@ async def text_stream():
             mock_aconnect_ws.assert_called_once()
             assert mock_aconnect_ws.call_args[0][0] == "/v1/tts/live"
 
+    @pytest.mark.filterwarnings("ignore::DeprecationWarning")
     @pytest.mark.asyncio
     @patch("fishaudio.resources.tts.aconnect_ws")
     async def test_stream_websocket_with_config(