diff --git a/changelog.d/10826.misc b/changelog.d/10826.misc
new file mode 100644
index 000000000000..53e56fc362f3
--- /dev/null
+++ b/changelog.d/10826.misc
@@ -0,0 +1,2 @@
+Opt out of cache expiry for `get_users_who_share_room_with_user`, to hopefully improve `/sync` performance when you
+haven't synced recently.