diff --git a/CHANGELOG.md b/CHANGELOG.md
index a839993c..2449c40d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+
+## 3.19.1 – 2025-03-11
+
+1. Fix bug where None is sent as delta in azure
+
 ## 3.19.0 – 2025-03-04
 
 1. Add support for tool calls in OpenAI and Anthropic.
diff --git a/posthog/ai/openai/openai.py b/posthog/ai/openai/openai.py
index ad425382..3d88b169 100644
--- a/posthog/ai/openai/openai.py
+++ b/posthog/ai/openai/openai.py
@@ -122,9 +122,10 @@ def generator():
                             usage_stats["cache_read_input_tokens"] = chunk.usage.prompt_tokens_details.cached_tokens
 
                     if hasattr(chunk, "choices") and chunk.choices and len(chunk.choices) > 0:
-                        content = chunk.choices[0].delta.content
-                        if content:
-                            accumulated_content.append(content)
+                        if chunk.choices[0].delta and chunk.choices[0].delta.content:
+                            content = chunk.choices[0].delta.content
+                            if content:
+                                accumulated_content.append(content)
 
                         # Process tool calls
                         tool_calls = getattr(chunk.choices[0].delta, "tool_calls", None)
diff --git a/posthog/ai/openai/openai_async.py b/posthog/ai/openai/openai_async.py
index b7f9ce11..9c2ed984 100644
--- a/posthog/ai/openai/openai_async.py
+++ b/posthog/ai/openai/openai_async.py
@@ -120,9 +120,10 @@ async def async_generator():
                             usage_stats["cache_read_input_tokens"] = chunk.usage.prompt_tokens_details.cached_tokens
 
                     if hasattr(chunk, "choices") and chunk.choices and len(chunk.choices) > 0:
-                        content = chunk.choices[0].delta.content
-                        if content:
-                            accumulated_content.append(content)
+                        if chunk.choices[0].delta and chunk.choices[0].delta.content:
+                            content = chunk.choices[0].delta.content
+                            if content:
+                                accumulated_content.append(content)
 
                         # Process tool calls
                         tool_calls = getattr(chunk.choices[0].delta, "tool_calls", None)
diff --git a/posthog/version.py b/posthog/version.py
index 7610a2fe..7b5d56f5 100644
--- a/posthog/version.py
+++ b/posthog/version.py
@@ -1,4 +1,4 @@
-VERSION = "3.19.0"
+VERSION = "3.19.1"
 
 if __name__ == "__main__":
     print(VERSION, end="")  # noqa: T201