diff --git a/CHANGELOG.md b/CHANGELOG.md
index cce40fd353981..8d6ecd97ef86c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## v1.7 [unreleased]
+### Features
+
+- [#3964](https://github.com/influxdata/telegraf/pull/3964): Add repl_oplog_window_s metric to mongodb input.
+
 ## v1.6 [unreleased]
 
 ### Release Notes