diff --git a/docs/release_notes.rst b/docs/release_notes.rst
index 8546386f26..7b0f8c8595 100644
--- a/docs/release_notes.rst
+++ b/docs/release_notes.rst
@@ -3,7 +3,7 @@ PUDL Release Notes
 =======================================================================================
 
 ---------------------------------------------------------------------------------------
-0.4.0 (2021-07-XX)
+0.4.0 (2021-08-16)
 ---------------------------------------------------------------------------------------
 This is a ridiculously large update including more than a year and a half's
 worth of work.