diff --git a/litellm/integrations/langfuse/langfuse.py b/litellm/integrations/langfuse/langfuse.py
index 296c2b5714e..f940af2a2ff 100644
--- a/litellm/integrations/langfuse/langfuse.py
+++ b/litellm/integrations/langfuse/langfuse.py
@@ -166,6 +166,17 @@ class LangFuseLogger:
             raise Exception(
                 f"\033[91mLangfuse not installed, try running 'pip install langfuse' to fix this error: {e}\n{traceback.format_exc()}\033[0m"
             )
+        import warnings
+
+        warnings.warn(
+            "LangFuseLogger (the 'langfuse' callback) uses the Langfuse Python SDK "
+            "and is deprecated in favour of LangfuseOtelLogger (the 'langfuse_otel' "
+            "callback), which sends spans directly over OpenTelemetry and is compatible "
+            "with Langfuse v4 Cloud Fast Preview. "
+            "Set success_callback=['langfuse_otel'] to switch to the new integration.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
         self.public_key, self.secret_key, self.langfuse_host = resolve_langfuse_credentials(
             langfuse_public_key=langfuse_public_key,
             langfuse_secret=langfuse_secret,
diff --git a/pyproject.toml b/pyproject.toml
index 34c1fec1c11..19e74db45ec 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>=2.59.7,<3.0",
+    "langfuse>=4.7,<5",
     "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==2.59.7",
+    "langfuse>=4.7,<5",
     "fastapi-offline==1.7.6",
     "fakeredis==2.34.1",
     "pytest-rerunfailures==15.1",
@@ -356,7 +356,7 @@ also_copy = [
 # Run the test suite once before mutation to gather line coverage, then skip
 # mutating lines no test exercises. Those mutants would survive regardless
 # (no test hits the line to kill them), so generating them wastes hours of CI.
-# The score now reads as "mutation score over covered code" — pair with a
+# The score now reads as "mutation score over covered code" — pair with a
 # line-coverage number when reporting.
 mutate_only_covered_lines = true
 # Disable rerun/parallel plugins for mutation runs: