diff --git a/changelog.d/20210.doc b/changelog.d/20210.doc
new file mode 100644
index 0000000000..3b0f828036
--- /dev/null
+++ b/changelog.d/20210.doc
@@ -0,0 +1 @@
+Document the endpoint for getting a single delayed event is workerisable.
diff --git a/docs/workers.md b/docs/workers.md
index 5914b9d1cb..5587ba9c6d 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -309,6 +309,9 @@ Additionally, the following REST endpoints can be handled for GET requests:
     # Admin API requests
     ^/_synapse/admin/v2/users/[^/]+$
 
+    # Unstable MSC4140 support
+    ^/_matrix/client/unstable/org.matrix.msc4140/delayed_events/[^/]+$
+
 Pagination requests can also be handled, but all requests for a given
 room must be routed to the same instance. Additionally, care must be taken to
 ensure that the purge history admin API is not used while pagination requests