diff --git a/CHANGELOG.md b/CHANGELOG.md
index cc5e3ae..d6f8477 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,13 @@
 CHANGELOG
 ---
 
+## 4.1.0
+
+- document requirement for MDS >=0.3
+- normalize epoch millisecond timestamp parsing
+- remove parsing for debug option for cache preservation (no longer needed)
+- accept local file timestamps as milliseconds
+
 ## 4.0.0
 
 - add custom zone aggregation for pickups and dropoffs
diff --git a/src/providers/local.js b/src/providers/local.js
index 10a3c7f..d161a61 100644
--- a/src/providers/local.js
+++ b/src/providers/local.js
@@ -28,8 +28,8 @@ async function trips(
           const data = chunk.toString();
           if (data.length) {
             var trip = JSON.parse(data);
-            trip.start_time = trip.start_time / 1000;
-            trip.end_time = trip.end_time / 1000;
+            trip.start_time = trip.start_time;
+            trip.end_time = trip.end_time;
 
             if (trip.start_time >= start && trip.start_time < stop) {
               trip = await tripMatch(trip, config, graph);
@@ -72,7 +72,7 @@ async function changes(
           const data = chunk.toString();
           if (data.length) {
             var change = JSON.parse(data);
-            change.event_time = change.event_time / 1000;
+            change.event_time = change.event_time;
             if (change.event_time >= start && change.event_time < stop) {
               change = await changeMatch(change, config, graph);
               const signature = crypto