diff --git a/pyproject.toml b/pyproject.toml
index 19e74db45ec..98d06108820 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -146,7 +146,7 @@ proxy-runtime = [
     "anthropic[vertex]>=0.84.0,<1.0",
     "grpcio==1.78.0",
     "prometheus-client>=0.20.0,<1.0",
-    "langfuse>=4.7,<5",
+    "langfuse>=2.59.7,<3.0",
     "opentelemetry-api==1.28.0",
     "opentelemetry-sdk==1.28.0",
     "opentelemetry-exporter-otlp==1.28.0",
@@ -195,7 +195,7 @@ dev = [
     "opentelemetry-sdk==1.28.0",
     "opentelemetry-exporter-otlp==1.28.0",
     "opentelemetry-instrumentation-fastapi==0.49b0",
-    "langfuse>=4.7,<5",
+    "langfuse==2.59.7",
     "fastapi-offline==1.7.6",
     "fakeredis==2.34.1",
     "pytest-rerunfailures==15.1",
diff --git a/tests/test_service_logger_otel.py b/tests/test_service_logger_otel.py
index 044d37d6781..d9c43bf71c9 100644
--- a/tests/test_service_logger_otel.py
+++ b/tests/test_service_logger_otel.py
@@ -25,9 +25,7 @@ class TestServiceLoggerOTEL(unittest.IsolatedAsyncioTestCase):
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_tracing")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_metrics")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_logs")
-    async def test_langfuse_otel_ignores_service_logs(
-        self, mock_logs, mock_metrics, mock_tracing
-    ):
+    async def test_langfuse_otel_ignores_service_logs(self, mock_logs, mock_metrics, mock_tracing):
         """
         Test that LangfuseOtelLogger overrides the service logging hooks with 'pass'.
         """
@@ -46,9 +44,7 @@ class TestServiceLoggerOTEL(unittest.IsolatedAsyncioTestCase):
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_tracing")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_metrics")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_logs")
-    async def test_langfuse_otel_does_not_create_proxy_request_span(
-        self, mock_logs, mock_metrics, mock_tracing
-    ):
+    async def test_langfuse_otel_does_not_create_proxy_request_span(self, mock_logs, mock_metrics, mock_tracing):
         """
         Test that LangfuseOtelLogger returns None for create_litellm_proxy_request_started_span.
 
@@ -73,9 +69,7 @@ class TestServiceLoggerOTEL(unittest.IsolatedAsyncioTestCase):
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_tracing")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_metrics")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_logs")
-    async def test_service_logging_shadowing_fix(
-        self, mock_logs, mock_metrics, mock_tracing
-    ):
+    async def test_service_logging_shadowing_fix(self, mock_logs, mock_metrics, mock_tracing):
         """
         Test the architectural fix: multiple OTEL loggers should receive logs independently.
         """
@@ -89,9 +83,7 @@ class TestServiceLoggerOTEL(unittest.IsolatedAsyncioTestCase):
         service_logging = ServiceLogging()
 
         # 3. Mock the base OpenTelemetry hook
-        with patch.object(
-            OpenTelemetry, "async_service_success_hook", new_callable=AsyncMock
-        ) as mock_base_hook:
+        with patch.object(OpenTelemetry, "async_service_success_hook", new_callable=AsyncMock) as mock_base_hook:
             # Trigger a service event
             await service_logging.async_service_success_hook(
                 service=ServiceTypes.DB,
@@ -112,9 +104,7 @@ class TestServiceLoggerOTEL(unittest.IsolatedAsyncioTestCase):
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_tracing")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_metrics")
     @patch("litellm.integrations.opentelemetry.OpenTelemetry._init_logs")
-    async def test_langfuse_otel_env_config_includes_v4_ingestion_header(
-        self, mock_logs, mock_metrics, mock_tracing
-    ):
+    async def test_langfuse_otel_env_config_includes_v4_ingestion_header(self, mock_logs, mock_metrics, mock_tracing):
         logger = LangfuseOtelLogger()
 
         headers = OpenTelemetry._get_headers_dictionary(logger.config.headers)
@@ -147,6 +137,49 @@ class TestServiceLoggerOTEL(unittest.IsolatedAsyncioTestCase):
         )
         self.assertTrue(headers["Authorization"].startswith("Basic "))
 
+    def test_langfuse_legacy_callback_emits_deprecation_warning(self):
+        """
+        Test that instantiating LangFuseLogger emits a DeprecationWarning
+        directing users to switch to the langfuse_otel callback.
+        """
+        import warnings
+        from unittest.mock import MagicMock, patch
+
+        mock_langfuse_module = MagicMock()
+        mock_langfuse_module.Langfuse = MagicMock()
+
+        with patch.dict(
+            "sys.modules",
+            {
+                "langfuse": mock_langfuse_module,
+                "langfuse.client": MagicMock(),
+            },
+        ):
+            with warnings.catch_warnings(record=True) as caught:
+                warnings.simplefilter("always")
+                from litellm.integrations.langfuse.langfuse import LangFuseLogger
+
+                with patch(
+                    "litellm.integrations.langfuse.langfuse.resolve_langfuse_credentials",
+                    return_value=("pk", "sk", "https://cloud.langfuse.com"),
+                ):
+                    LangFuseLogger(
+                        langfuse_public_key="pk",
+                        langfuse_secret="sk",
+                        langfuse_host="https://cloud.langfuse.com",
+                        allow_env_credentials=False,
+                    )
+
+            deprecation_warnings = [w for w in caught if issubclass(w.category, DeprecationWarning)]
+            self.assertTrue(
+                len(deprecation_warnings) >= 1,
+                "Expected at least one DeprecationWarning to be emitted",
+            )
+            self.assertIn(
+                "langfuse_otel",
+                str(deprecation_warnings[0].message),
+            )
+
 
 if __name__ == "__main__":
     unittest.main()