diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index 554e51a8..d46d35bf 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -85,7 +85,7 @@ Running the test app
 --------------------
 
 Note: this has not been tested in a while. Instead, the
-[scout-test-apps repo](https://github.com/tim-schilling/scout-test-apps) has
+[scout-test-apps repo](https://github.com/scoutapp/scout-test-apps) has
 been used with many individual scout apps.
 
 Add the following env variables:
@@ -133,7 +133,6 @@ architectures. Its documentation is excellent.
 Documentation
 -------------
 
-The user documentation is stored in the [slate_apm_help
-repo](https://github.com/scoutapp/slate_apm_help) in the
-`source/_includes/python.md` file. Make relevant changes there when developing
-features.
+The user documentation is stored in the [scout-documentation](https://github.com/scoutapp/scout-documentation) repo.
+It is private to the Scout Monitoring team; if you want to submit a feature feel free to
+send us some Markdown and we will get it added.
diff --git a/src/scout_apm/core/agent/commands.py b/src/scout_apm/core/agent/commands.py
index bd4c5836..6de921f8 100644
--- a/src/scout_apm/core/agent/commands.py
+++ b/src/scout_apm/core/agent/commands.py
@@ -13,13 +13,14 @@
 
 def format_dt_for_core_agent(event_time: dt.datetime) -> str:
     """
-    Returns expected format for Core Agent compatibility. Agent expects UTC datetime
-    with 'Z' suffix. Coerce any tz-aware datetime to UTC just in case.
+    Returns expected format for Core Agent compatibility.
+    Coerce any tz-aware datetime to UTC just in case.
     """
-    # if we somehow got a non-UTC datetime, convert it to UTC
-    if event_time.tzinfo is not None:
+    # if we somehow got a naive datetime, convert it to UTC
+    if event_time.tzinfo is None:
+        logger.warning("Naive datetime passed to format_dt_for_core_agent")
         event_time = event_time.astimezone(dt.timezone.utc)
-    return event_time.strftime("%Y-%m-%dT%H:%M:%SZ")
+    return event_time.isoformat()
 
 
 class Register(object):