diff --git a/changelog.d/6905.doc b/changelog.d/6905.doc
new file mode 100644
index 0000000000..ca10b38301
--- /dev/null
+++ b/changelog.d/6905.doc
@@ -0,0 +1 @@
+Mention in `ACME.md` that ACMEv1 is deprecated and explain what it means for Synapse admins.