diff -u b/core/CHANGELOG.txt b/core/CHANGELOG.txt
--- b/core/CHANGELOG.txt
+++ b/core/CHANGELOG.txt
@@ -16,6 +16,21 @@
 [See the change record](https://www.drupal.org/node/2891902), which explains
 the broken scenario in detail, and describes how sites can opt out.
 
+## Note about browser requirements
+
+In April 2017, Microsoft discontinued all support for Internet Explorer 9 and
+10. Therefore, [Drupal 8.4 has as well] (https://www.drupal.org/node/2897971).
+Drupal 8.4 still mostly works in these browser versions, but existing and newly
+discovered bugs that only affect these browser versions will no longer be
+fixed, and existing workarounds in Drupal core for these browser versions will
+be removed beginning in Drupal 8.5.
+
+Additionally, Drupal 8's [browser requirements documentation page] (https://www.drupal.org/docs/8/system-requirements/browser-requirements)
+currently lists incorrect information regarding very outdated browser versions
+such as Safari 5 and Firefox 5. Clarifications to the policy and documentation
+are [in progress] (https://www.drupal.org/node/2390621), with a goal of being
+finalized before 8.4.0-rc1.
+
 ## New stable modules
 
 The following modules, previously considered experimental, are now stable and