diff --git a/docs/en/04_Changelogs/4.2.0.md b/docs/en/04_Changelogs/4.2.0.md
index b63fea5b1..1b6e5e6df 100644
--- a/docs/en/04_Changelogs/4.2.0.md
+++ b/docs/en/04_Changelogs/4.2.0.md
@@ -357,6 +357,9 @@ class PageController extends ContentController
    Note this is different from `Vary: Accept-Encoding`,
    which is important for compression (e.g. gzip), and usually added by
    other layers such as Apache's mod_gzip.
+ * No longer sets `Last-Modified` date in HTTP response headers in `DataObject::__construct()`.
+   Uses `ETag` calculation based on response body which is more accurate,
+   and resilient against partial and object caching which can produce stale `Last-Modified` values. 
  * DataObject no longer automatically invokes `HTTP::register_modification_date`
    with LastModified on construction. User code should instead invoke
    `HTTPCacheControlMiddleware::singleton()->registerModificationDate()` explicitly.